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 = 621 
WHERE 
  cscart_products_categories.product_id IN (
    8007, 7724, 7897, 7952, 7959, 7972, 7974, 
    8009, 8010, 7948, 7949, 7953, 7962, 
    7964, 7968, 8005, 8013, 7231, 7249, 
    7391, 7947, 7955, 7957, 7958, 7975, 
    7992, 7024, 7355, 7893, 7954, 7970, 
    7977, 7196, 7350, 8080, 7227, 7324, 
    7500, 7956, 8006, 7022, 7080, 7191, 
    7250, 7320, 7340, 7352, 7888, 8110, 
    8192, 8364, 7021, 7192, 7256, 7506, 
    7850, 7230, 7319, 7343, 7386, 7900, 
    8214, 7189, 7226, 7348, 7356, 7390, 
    7965, 7232, 7237, 7344, 7383, 7389, 
    7887, 7894, 8207, 9909, 7193, 7262, 
    8069
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00324

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "140.76"
    },
    "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": 105,
            "rows_produced_per_join": 105,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (8007,7724,7897,7952,7959,7972,7974,8009,8010,7948,7949,7953,7962,7964,7968,8005,8013,7231,7249,7391,7947,7955,7957,7958,7975,7992,7024,7355,7893,7954,7970,7977,7196,7350,8080,7227,7324,7500,7956,8006,7022,7080,7191,7250,7320,7340,7352,7888,8110,8192,8364,7021,7192,7256,7506,7850,7230,7319,7343,7386,7900,8214,7189,7226,7348,7356,7390,7965,7232,7237,7344,7383,7389,7887,7894,8207,9909,7193,7262,8069))",
            "cost_info": {
              "read_cost": "56.76",
              "eval_cost": "10.50",
              "prefix_cost": "67.26",
              "data_read_per_join": "1K"
            },
            "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": 105,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "26.25",
              "eval_cost": "10.50",
              "prefix_cost": "104.01",
              "data_read_per_join": "1K"
            },
            "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": 5,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "26.25",
              "eval_cost": "0.53",
              "prefix_cost": "140.76",
              "data_read_per_join": "16K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}