SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.product 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    5204, 5205, 5203, 5201, 5859, 5199, 3894, 
    5173, 5175, 5174
  ) 
  AND cscart_product_descriptions.lang_code = 'de'

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "7.01"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 10,
      "rows_produced_per_join": 10,
      "filtered": "100.00",
      "index_condition": "((`dbggbern`.`cscart_product_descriptions`.`product_id` in (5204,5205,5203,5201,5859,5199,3894,5173,5175,5174)) and (`dbggbern`.`cscart_product_descriptions`.`lang_code` = 'de'))",
      "cost_info": {
        "read_cost": "6.01",
        "eval_cost": "1.00",
        "prefix_cost": "7.01",
        "data_read_per_join": "38K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "product"
      ]
    }
  }
}