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 = 7170 
WHERE 
  cscart_products_categories.product_id IN (
    84803, 91082, 82718, 82719, 83456, 83457, 
    89764, 83073, 83626, 90909, 90988, 
    85083, 85169, 85215, 85261, 86178, 
    86201, 86502, 86778, 82633, 82634, 
    83530, 83531, 85316, 85413, 85464, 
    85515, 86470, 86746, 86973, 87034, 
    89074, 89820, 89872, 89944, 91510, 
    82851, 82862, 82924, 82935, 82997, 
    83008, 83444, 83449, 83513, 83521, 
    85123, 84329, 84330, 86195, 86218, 
    86527, 86803, 89079, 89080, 82716, 
    83454, 85362, 86609, 86610, 86678, 
    86679, 83559, 83560, 83561, 83562, 
    89770, 89771, 84814, 84815, 84832, 
    84833, 84844, 84845, 91137, 91223, 
    91278, 85320, 85321, 85417, 85418, 
    85468, 85469, 85519, 85520, 86184, 
    86185, 86207, 86208, 86508, 86509, 
    86784, 86785, 83053, 83055, 83602
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00277

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "92.82"
    },
    "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": 163,
            "rows_produced_per_join": 163,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "16.62",
              "eval_cost": "16.30",
              "prefix_cost": "32.92",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (84803,91082,82718,82719,83456,83457,89764,83073,83626,90909,90988,85083,85169,85215,85261,86178,86201,86502,86778,82633,82634,83530,83531,85316,85413,85464,85515,86470,86746,86973,87034,89074,89820,89872,89944,91510,82851,82862,82924,82935,82997,83008,83444,83449,83513,83521,85123,84329,84330,86195,86218,86527,86803,89079,89080,82716,83454,85362,86609,86610,86678,86679,83559,83560,83561,83562,89770,89771,84814,84815,84832,84833,84844,84845,91137,91223,91278,85320,85321,85417,85418,85468,85469,85519,85520,86184,86185,86207,86208,86508,86509,86784,86785,83053,83055,83602))"
          }
        },
        {
          "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": "40.75",
              "eval_cost": "0.82",
              "prefix_cost": "89.97",
              "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": "2.04",
              "eval_cost": "0.82",
              "prefix_cost": "92.82",
              "data_read_per_join": "130"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}