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 (
    6149, 5685, 6148, 6150, 6151, 5721, 5722, 
    5723, 5724, 5725, 5726, 5944, 5945, 
    5946, 5947, 6119, 6120, 6121, 6122, 
    6123, 6124, 6125, 5948, 6128, 6127, 
    6126, 6129, 6130, 6131, 6132, 6133, 
    6134, 6135, 5952, 6138, 6137, 6136, 
    6139, 6140, 6141, 6142, 6143, 6026, 
    6025, 6027, 6028, 6029, 6030, 6031, 
    6032, 6033, 6034, 6035, 6036, 6037, 
    6038, 6039, 6040, 6041, 6042, 6043, 
    6044, 6045, 6046, 6047, 6048, 6049, 
    6050, 6051, 6052, 6053, 6054, 6055, 
    6056, 6057, 6058, 6059, 6069, 6070, 
    6071, 6094, 6095, 6110, 6111, 5683, 
    6152, 6153, 6154, 6155, 6156, 6157, 
    6158, 6159, 6164, 6165, 6166, 6167, 
    6168, 6169, 6170, 6171, 6172, 6173, 
    6174, 6175, 6176, 6177, 6178, 6179, 
    6180, 6181, 6182, 6183, 6184
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00502

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "254.11"
    },
    "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": 282,
            "rows_produced_per_join": 282,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (6149,5685,6148,6150,6151,5721,5722,5723,5724,5725,5726,5944,5945,5946,5947,6119,6120,6121,6122,6123,6124,6125,5948,6128,6127,6126,6129,6130,6131,6132,6133,6134,6135,5952,6138,6137,6136,6139,6140,6141,6142,6143,6026,6025,6027,6028,6029,6030,6031,6032,6033,6034,6035,6036,6037,6038,6039,6040,6041,6042,6043,6044,6045,6046,6047,6048,6049,6050,6051,6052,6053,6054,6055,6056,6057,6058,6059,6069,6070,6071,6094,6095,6110,6111,5683,6152,6153,6154,6155,6156,6157,6158,6159,6164,6165,6166,6167,6168,6169,6170,6171,6172,6173,6174,6175,6176,6177,6178,6179,6180,6181,6182,6183,6184))",
            "cost_info": {
              "read_cost": "127.21",
              "eval_cost": "28.20",
              "prefix_cost": "155.41",
              "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": 14,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "70.50",
              "eval_cost": "1.41",
              "prefix_cost": "254.11",
              "data_read_per_join": "44K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}