SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids, 
  product_position_source.position AS position 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 449 
WHERE 
  cscart_products_categories.product_id IN (
    5696, 
    5621, 
    5892, 
    5719, 
    5706, 
    5720, 
    5703, 
    4894, 
    4962, 
    5691, 
    5687, 
    3733, 
    4915, 
    3589, 
    4976, 
    3811, 
    6093, 
    6194, 
    4935, 
    3734, 
    3641, 
    5700, 
    6064, 
    3798, 
    4931, 
    3730, 
    3638, 
    3729, 
    3851, 
    6204, 
    3942, 
    3732, 
    3448, 
    3728, 
    3852, 
    3850, 
    3731, 
    3642, 
    3943, 
    3623, 
    3645, 
    3637, 
    3950, 
    6074, 
    3644, 
    3864, 
    3940, 
    3865, 
    6117, 
    3869, 
    3948, 
    3941, 
    6068, 
    3951, 
    5812, 
    3949, 
    6097, 
    8612, 
    6073, 
    8464, 
    8469, 
    10025, 
    8724, 
    8445, 
    8811, 
    8441, 
    8446, 
    8440, 
    8593, 
    8595, 
    8444, 
    8471, 
    8594, 
    8457, 
    8828, 
    8466, 
    8831, 
    8276, 
    8365, 
    8585, 
    8615, 
    8729, 
    8730, 
    8797, 
    8810, 
    8814, 
    8829, 
    8244, 
    8277, 
    8377, 
    8403, 
    8431, 
    8587, 
    8798, 
    8271, 
    8274, 
    8278, 
    8333, 
    8389, 
    8430, 
    8516, 
    8518, 
    8537, 
    8755, 
    10044, 
    8334, 
    8383, 
    8462, 
    8539, 
    10046, 
    8401, 
    8386, 
    11588, 
    11597, 
    11608, 
    11580, 
    11609, 
    11589, 
    11591, 
    11596, 
    11604, 
    11611, 
    11582, 
    11584, 
    11586, 
    11595, 
    11606, 
    11603
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00292

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "318.13"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 350,
            "rows_produced_per_join": 350,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (5696,5621,5892,5719,5706,5720,5703,4894,4962,5691,5687,3733,4915,3589,4976,3811,6093,6194,4935,3734,3641,5700,6064,3798,4931,3730,3638,3729,3851,6204,3942,3732,3448,3728,3852,3850,3731,3642,3943,3623,3645,3637,3950,6074,3644,3864,3940,3865,6117,3869,3948,3941,6068,3951,5812,3949,6097,8612,6073,8464,8469,10025,8724,8445,8811,8441,8446,8440,8593,8595,8444,8471,8594,8457,8828,8466,8831,8276,8365,8585,8615,8729,8730,8797,8810,8814,8829,8244,8277,8377,8403,8431,8587,8798,8271,8274,8278,8333,8389,8430,8516,8518,8537,8755,10044,8334,8383,8462,8539,10046,8401,8386,11588,11597,11608,11580,11609,11589,11591,11596,11604,11611,11582,11584,11586,11595,11606,11603))",
            "cost_info": {
              "read_cost": "154.51",
              "eval_cost": "35.00",
              "prefix_cost": "189.51",
              "data_read_per_join": "5K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        },
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "softwarepirmam_hewadelivard_cscart_4.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 17,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "87.50",
              "eval_cost": "1.75",
              "prefix_cost": "312.01",
              "data_read_per_join": "54K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`storefront_id` in (0,1)) and ((`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids`))) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "product_position_source",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id",
              "product_id"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "softwarepirmam_hewadelivard_cscart_4.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 17,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "4.38",
              "eval_cost": "1.75",
              "prefix_cost": "318.14",
              "data_read_per_join": "280"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}