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 = 7157 
WHERE 
  cscart_products_categories.product_id IN (
    91846, 91847, 86891, 91868, 91849, 91850, 
    91851, 91852, 91853, 91854, 91855, 
    91857, 91858, 91859, 91860, 91861, 
    91862, 91863, 92227, 82402, 92210, 
    85577, 92373, 92383, 92384, 92385, 
    92386, 92387, 92388, 92389, 91889, 
    91890, 91891, 92333, 92334, 92335, 
    92336, 86888, 92365, 86890, 91864, 
    92374, 85576, 85584, 85572, 86900, 
    85592, 85546
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00532

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "86.57"
    },
    "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": 152,
            "rows_produced_per_join": 152,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "15.52",
              "eval_cost": "15.20",
              "prefix_cost": "30.72",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (91846,91847,86891,91868,91849,91850,91851,91852,91853,91854,91855,91857,91858,91859,91860,91861,91862,91863,92227,82402,92210,85577,92373,92383,92384,92385,92386,92387,92388,92389,91889,91890,91891,92333,92334,92335,92336,86888,92365,86890,91864,92374,85576,85584,85572,86900,85592,85546))"
          }
        },
        {
          "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": 7,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "38.00",
              "eval_cost": "0.76",
              "prefix_cost": "83.92",
              "data_read_per_join": "19K"
            },
            "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": 7,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.90",
              "eval_cost": "0.76",
              "prefix_cost": "86.58",
              "data_read_per_join": "121"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}