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 = 7204 
WHERE 
  cscart_products_categories.product_id IN (
    87917, 88036, 87971, 84756, 84757, 84861, 
    84862, 87900, 87901, 87915, 88088, 
    88056, 88057, 88058, 84851, 88037, 
    88059, 88060, 87907, 87940, 88091, 
    88090, 88087, 88086, 94451, 94798, 
    94799, 94800, 94801, 94823, 94824, 
    94827, 94828, 94829, 94830, 94831, 
    95736, 95743, 95744, 95745, 95746, 
    95747, 95748, 95749, 95750, 95751, 
    95752, 95813, 95814, 95815, 95816, 
    95817, 95818, 95833, 95834, 95835, 
    95836, 95837, 95838, 95839, 95840, 
    95841, 95842, 95843, 95844, 95845, 
    95846, 95847, 95848, 95849, 95850, 
    95851, 95852, 95853, 95854, 95855, 
    95856, 95857, 95858, 95859, 95860, 
    95861, 95862, 95863, 95864, 97426, 
    97427, 97428, 97429, 97430, 97431, 
    97432, 97433, 97434, 97435, 97436
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01548

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "105.60"
    },
    "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": 117,
            "rows_produced_per_join": 117,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "12.00",
              "eval_cost": "11.70",
              "prefix_cost": "23.70",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (87917,88036,87971,84756,84757,84861,84862,87900,87901,87915,88088,88056,88057,88058,84851,88037,88059,88060,87907,87940,88091,88090,88087,88086,94451,94798,94799,94800,94801,94823,94824,94827,94828,94829,94830,94831,95736,95743,95744,95745,95746,95747,95748,95749,95750,95751,95752,95813,95814,95815,95816,95817,95818,95833,95834,95835,95836,95837,95838,95839,95840,95841,95842,95843,95844,95845,95846,95847,95848,95849,95850,95851,95852,95853,95854,95855,95856,95857,95858,95859,95860,95861,95862,95863,95864,97426,97427,97428,97429,97430,97431,97432,97433,97434,97435,97436))"
          }
        },
        {
          "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": 117,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "29.25",
              "eval_cost": "11.70",
              "prefix_cost": "64.65",
              "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": [
              "nuie_scalesta_net.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 5,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "29.25",
              "eval_cost": "0.59",
              "prefix_cost": "105.60",
              "data_read_per_join": "15K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}