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 = 7210 
WHERE 
  cscart_products_categories.product_id IN (
    99127, 99128, 99129, 99130, 99131, 99132, 
    99134, 99135, 99143, 99144, 99162, 
    99163, 99164, 99165, 99166, 99168, 
    99171, 99172, 99173, 99174, 99175, 
    99176, 99177, 99178, 99179, 99180, 
    99182, 99183, 99184, 99192, 99193, 
    99194, 99197, 99198, 99199, 99200, 
    99203, 99204, 99206, 99207, 99208, 
    99209, 99214, 99215, 99218, 99219, 
    99221, 99222, 99223, 99224, 99225, 
    99226, 99227, 99228, 99229, 99230, 
    99231, 99232, 99233, 99234, 99235, 
    99236, 99237, 99238, 99240, 99242, 
    99243, 99244, 99245, 99246, 99247, 
    99249, 99250, 99251, 99252, 99253, 
    99254, 99255, 99256, 99258, 99259, 
    99260, 99261, 99263, 99264, 99265, 
    99266, 99268, 99269, 99270, 99271, 
    99272, 99273, 99274, 99275, 99276
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00279

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "107.02"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 188,
            "rows_produced_per_join": 188,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "19.13",
              "eval_cost": "18.80",
              "prefix_cost": "37.93",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (99127,99128,99129,99130,99131,99132,99134,99135,99143,99144,99162,99163,99164,99165,99166,99168,99171,99172,99173,99174,99175,99176,99177,99178,99179,99180,99182,99183,99184,99192,99193,99194,99197,99198,99199,99200,99203,99204,99206,99207,99208,99209,99214,99215,99218,99219,99221,99222,99223,99224,99225,99226,99227,99228,99229,99230,99231,99232,99233,99234,99235,99236,99237,99238,99240,99242,99243,99244,99245,99246,99247,99249,99250,99251,99252,99253,99254,99255,99256,99258,99259,99260,99261,99263,99264,99265,99266,99268,99269,99270,99271,99272,99273,99274,99275,99276))"
          }
        },
        {
          "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": [
              "nuie_scalesta_net.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 9,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "47.00",
              "eval_cost": "0.94",
              "prefix_cost": "103.73",
              "data_read_per_join": "24K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`nuie_scalesta_net`.`cscart_categories`.`storefront_id` in (0,1)) and ((`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`))) and (`nuie_scalesta_net`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "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",
              "nuie_scalesta_net.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 9,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "2.35",
              "eval_cost": "0.94",
              "prefix_cost": "107.02",
              "data_read_per_join": "150"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}