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 = 7336 
WHERE 
  cscart_products_categories.product_id IN (
    94761, 94763, 94765, 94816, 94950, 94951, 
    94956, 94957, 95566, 95569, 95571, 
    95574, 95575, 95578, 95579, 95580, 
    95581, 95587, 95588, 95589, 95590, 
    95591, 95629, 95630, 95631, 95632, 
    95633, 95634, 95635, 95636, 95637, 
    95641, 95642, 95643, 95644, 95647, 
    95648, 95649, 95650, 95651, 95652, 
    95655, 95656, 95657, 95658, 95659, 
    95660, 95935
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01595

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "128.89"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "5.29"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 208,
            "rows_produced_per_join": 8,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "20.72",
              "eval_cost": "0.83",
              "prefix_cost": "21.55",
              "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": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "nuie_scalesta_net.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 117,
            "rows_produced_per_join": 5,
            "filtered": "0.54",
            "cost_info": {
              "read_cost": "2.33",
              "eval_cost": "0.53",
              "prefix_cost": "121.75",
              "data_read_per_join": "84"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (94761,94763,94765,94816,94950,94951,94956,94957,95566,95569,95571,95574,95575,95578,95579,95580,95581,95587,95588,95589,95590,95591,95629,95630,95631,95632,95633,95634,95635,95636,95637,95641,95642,95643,95644,95647,95648,95649,95650,95651,95652,95655,95656,95657,95658,95659,95660,95935))"
          }
        },
        {
          "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": 5,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.32",
              "eval_cost": "0.53",
              "prefix_cost": "123.60",
              "data_read_per_join": "84"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}