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 
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') 
WHERE 
  cscart_products_categories.product_id IN (
    4108, 4107, 3734, 4109, 3798, 4110, 4111, 
    3811, 4899, 4898, 4897, 4896, 4894, 
    4915, 4917, 4924, 4923, 4922, 4921, 
    4920, 4919, 4918, 4925, 4927, 4926, 
    4941, 4940, 4939, 4935, 4973, 4972, 
    4971, 4970, 4969, 4968, 4967, 4966, 
    4965, 4964, 4963, 4962, 4987, 4986, 
    4985, 4984, 4977, 4976, 4981, 4980, 
    4979, 4978, 4982, 4983, 5618, 5619, 
    5620, 5621, 5687, 5688, 5689, 5690, 
    5691, 5692, 5693, 5694, 5696, 5697, 
    5698, 5699, 5700, 5701, 5702, 5703, 
    5704, 5705, 6204, 5894, 5893, 5892, 
    6064, 6065, 6066, 6067, 6074, 6075, 
    5956, 6087, 6088, 6089, 6090, 6091, 
    6092, 6093, 6117, 6118, 6196, 6195, 
    6194, 6197, 6198, 6199, 6200, 6201, 
    6202
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00367

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "230.81"
    },
    "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": 256,
            "rows_produced_per_join": 256,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (4108,4107,3734,4109,3798,4110,4111,3811,4899,4898,4897,4896,4894,4915,4917,4924,4923,4922,4921,4920,4919,4918,4925,4927,4926,4941,4940,4939,4935,4973,4972,4971,4970,4969,4968,4967,4966,4965,4964,4963,4962,4987,4986,4985,4984,4977,4976,4981,4980,4979,4978,4982,4983,5618,5619,5620,5621,5687,5688,5689,5690,5691,5692,5693,5694,5696,5697,5698,5699,5700,5701,5702,5703,5704,5705,6204,5894,5893,5892,6064,6065,6066,6067,6074,6075,5956,6087,6088,6089,6090,6091,6092,6093,6117,6118,6196,6195,6194,6197,6198,6199,6200,6201,6202))",
            "cost_info": {
              "read_cost": "115.61",
              "eval_cost": "25.60",
              "prefix_cost": "141.21",
              "data_read_per_join": "4K"
            },
            "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": 12,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "64.00",
              "eval_cost": "1.28",
              "prefix_cost": "230.81",
              "data_read_per_join": "40K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}