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 = 7320 
WHERE 
  cscart_products_categories.product_id IN (
    94582, 94853, 95756, 95758, 95770, 95771, 
    95772, 95774, 95775, 95776, 95824, 
    95825, 95826, 96573, 97608, 97610, 
    97611, 97612, 97613, 97614, 97615, 
    97617, 97618, 97629, 97630, 97631, 
    97633, 97635, 97636, 97637, 97640, 
    97641, 97642, 97643, 97644, 97645, 
    97646, 97647, 97648, 97649, 97650, 
    97651, 97652, 97653, 97654, 97655, 
    97656, 97657, 97658, 97659, 97660, 
    97661, 97662, 97663, 97664, 97665, 
    97666, 97667, 97668, 97669, 97670, 
    97671, 97672, 97673, 97674, 97675, 
    97676, 97677, 97678, 97679, 97680, 
    97681, 97697, 97699, 97700, 97701, 
    97702, 97706, 99112, 99115, 99116, 
    99118, 99119, 99130, 99132, 99134, 
    99143, 99164, 99166, 99173, 99175, 
    99180, 99192, 99194, 99197, 99200
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00256

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "109.29"
    },
    "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": 192,
            "rows_produced_per_join": 192,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "19.53",
              "eval_cost": "19.20",
              "prefix_cost": "38.73",
              "data_read_per_join": "3K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (94582,94853,95756,95758,95770,95771,95772,95774,95775,95776,95824,95825,95826,96573,97608,97610,97611,97612,97613,97614,97615,97617,97618,97629,97630,97631,97633,97635,97636,97637,97640,97641,97642,97643,97644,97645,97646,97647,97648,97649,97650,97651,97652,97653,97654,97655,97656,97657,97658,97659,97660,97661,97662,97663,97664,97665,97666,97667,97668,97669,97670,97671,97672,97673,97674,97675,97676,97677,97678,97679,97680,97681,97697,97699,97700,97701,97702,97706,99112,99115,99116,99118,99119,99130,99132,99134,99143,99164,99166,99173,99175,99180,99192,99194,99197,99200))"
          }
        },
        {
          "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": "48.00",
              "eval_cost": "0.96",
              "prefix_cost": "105.93",
              "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": "2.40",
              "eval_cost": "0.96",
              "prefix_cost": "109.29",
              "data_read_per_join": "153"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}