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 (
    4975, 4974, 4998, 4995, 5039, 5038, 4991, 
    5870, 5661, 7608, 7279, 7612, 7614, 
    7613, 7248, 7624, 7277, 7623, 2432, 
    8485, 8484, 8483, 2455, 8488, 8487, 
    8486, 8490, 8489, 2438, 2459, 8492, 
    8491, 8493, 1538, 8496, 1517, 8498, 
    8497, 1532, 8502, 8501, 8499, 1528, 
    8505, 8503, 5346
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00277

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "162.71"
    },
    "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": 189,
            "rows_produced_per_join": 189,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (4975,4974,4998,4995,5039,5038,4991,5870,5661,7608,7279,7612,7614,7613,7248,7624,7277,7623,2432,8485,8484,8483,2455,8488,8487,8486,8490,8489,2438,2459,8492,8491,8493,1538,8496,1517,8498,8497,1532,8502,8501,8499,1528,8505,8503,5346))",
            "cost_info": {
              "read_cost": "77.66",
              "eval_cost": "18.90",
              "prefix_cost": "96.56",
              "data_read_per_join": "2K"
            },
            "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": 9,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "47.25",
              "eval_cost": "0.95",
              "prefix_cost": "162.71",
              "data_read_per_join": "29K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}