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 = 448 
WHERE 
  cscart_products_categories.product_id IN (
    3354, 3308, 3397, 3841, 3212, 3928, 3660, 
    3828, 3518, 3918, 3400, 3232, 3740, 
    3743, 3741, 3440, 3441, 10078, 3768, 
    3747, 3406, 3827, 3738, 3403, 3443, 
    3737, 3655, 3658, 3769, 3745, 3767, 
    3950, 3659, 3766, 3739, 3444, 3785, 
    3442, 3787, 3770, 3447, 3793, 3450, 
    3772, 3795, 3788, 3439, 3446, 3794, 
    3948, 3449, 3871, 3786, 3867, 3951, 
    3949, 3881, 11629, 8597, 8280, 8443, 
    8596, 11632, 8405, 8584, 8588, 8437, 
    8515, 8542, 10446, 10492, 11623, 11624, 
    11625, 11626, 11627, 11628, 11631
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00781

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "307.01"
    },
    "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": 250,
            "rows_produced_per_join": 250,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (3354,3308,3397,3841,3212,3928,3660,3828,3518,3918,3400,3232,3740,3743,3741,3440,3441,10078,3768,3747,3406,3827,3738,3403,3443,3737,3655,3658,3769,3745,3767,3950,3659,3766,3739,3444,3785,3442,3787,3770,3447,3793,3450,3772,3795,3788,3439,3446,3794,3948,3449,3871,3786,3867,3951,3949,3881,11629,8597,8280,8443,8596,11632,8405,8584,8588,8437,8515,8542,10446,10492,11623,11624,11625,11626,11627,11628,11631))",
            "cost_info": {
              "read_cost": "107.01",
              "eval_cost": "25.00",
              "prefix_cost": "132.01",
              "data_read_per_join": "3K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        },
        {
          "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": 250,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "62.50",
              "eval_cost": "25.00",
              "prefix_cost": "219.51",
              "data_read_per_join": "3K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        },
        {
          "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": 12,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "62.50",
              "eval_cost": "1.25",
              "prefix_cost": "307.01",
              "data_read_per_join": "39K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}