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 = 7148 
WHERE 
  cscart_products_categories.product_id IN (
    84257, 84258, 87575, 87576, 87590, 87591, 
    87605, 87606, 88786, 88787, 85598, 
    90826, 85578, 87656, 87670, 87677, 
    87684, 87705, 87716, 87717, 87730, 
    87731, 90022, 90024, 90038, 90040, 
    90041, 91970, 91973, 90329, 90330, 
    90331, 90333, 90334, 90337, 90338, 
    90339, 90340, 90341, 90342, 90345, 
    90346, 90347, 90348, 85590, 86358, 
    92342, 87881, 91985, 91986, 91987, 
    91988, 91989, 91990, 91991, 92241, 
    92242, 92243, 92244, 92246, 92251, 
    92483, 92484, 91969, 91971, 91972, 
    91974, 91975, 92440, 85595, 86250, 
    86810, 82557, 84045, 86354, 84775, 
    84779, 84788, 84797, 87654, 87655, 
    87668, 87669, 87675, 87676, 87682, 
    87683, 87703, 87704, 87713, 87715, 
    87727, 87729, 88692, 88693, 88739
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00258

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "95.66"
    },
    "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": 168,
            "rows_produced_per_join": 168,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "17.12",
              "eval_cost": "16.80",
              "prefix_cost": "33.92",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (84257,84258,87575,87576,87590,87591,87605,87606,88786,88787,85598,90826,85578,87656,87670,87677,87684,87705,87716,87717,87730,87731,90022,90024,90038,90040,90041,91970,91973,90329,90330,90331,90333,90334,90337,90338,90339,90340,90341,90342,90345,90346,90347,90348,85590,86358,92342,87881,91985,91986,91987,91988,91989,91990,91991,92241,92242,92243,92244,92246,92251,92483,92484,91969,91971,91972,91974,91975,92440,85595,86250,86810,82557,84045,86354,84775,84779,84788,84797,87654,87655,87668,87669,87675,87676,87682,87683,87703,87704,87713,87715,87727,87729,88692,88693,88739))"
          }
        },
        {
          "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": 8,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "42.00",
              "eval_cost": "0.84",
              "prefix_cost": "92.72",
              "data_read_per_join": "21K"
            },
            "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": 8,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "2.10",
              "eval_cost": "0.84",
              "prefix_cost": "95.66",
              "data_read_per_join": "134"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}