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 = 7191 
WHERE 
  cscart_products_categories.product_id IN (
    87296, 87297, 85852, 85853, 85862, 85863, 
    91007, 91008, 91019, 91020, 91031, 
    91032, 91044, 91045, 85842, 85843, 
    91004, 91005, 91016, 91017, 91028, 
    91029, 91040, 91041, 91042, 90008, 
    90564, 90570, 90576, 84678, 87304, 
    87305, 87316, 87317, 87328, 87329, 
    87340, 87341, 89818, 89819, 89870, 
    89871, 89942, 89943, 91508, 91509, 
    83083, 83084, 83611, 83612, 90922, 
    90923, 91001, 91002, 87292, 87293, 
    89816, 89868, 89940, 91506, 85848, 
    85849, 85858, 85859, 83081, 83609, 
    90920, 90999, 89997, 90004, 86471, 
    86472, 86747, 86748, 85838, 85839, 
    90546, 89817, 89869, 89941, 91507, 
    83082, 83610, 90921, 91000, 86469, 
    86745, 84808, 84809, 84826, 84827, 
    84838, 84839, 91106, 91192, 91247
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00388

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "113.26"
    },
    "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": 199,
            "rows_produced_per_join": 199,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "20.23",
              "eval_cost": "19.90",
              "prefix_cost": "40.13",
              "data_read_per_join": "3K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (87296,87297,85852,85853,85862,85863,91007,91008,91019,91020,91031,91032,91044,91045,85842,85843,91004,91005,91016,91017,91028,91029,91040,91041,91042,90008,90564,90570,90576,84678,87304,87305,87316,87317,87328,87329,87340,87341,89818,89819,89870,89871,89942,89943,91508,91509,83083,83084,83611,83612,90922,90923,91001,91002,87292,87293,89816,89868,89940,91506,85848,85849,85858,85859,83081,83609,90920,90999,89997,90004,86471,86472,86747,86748,85838,85839,90546,89817,89869,89941,91507,83082,83610,90921,91000,86469,86745,84808,84809,84826,84827,84838,84839,91106,91192,91247))"
          }
        },
        {
          "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": "49.75",
              "eval_cost": "1.00",
              "prefix_cost": "109.78",
              "data_read_per_join": "25K"
            },
            "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": "2.49",
              "eval_cost": "1.00",
              "prefix_cost": "113.26",
              "data_read_per_join": "159"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}