SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    10228, 10229, 10232, 10233, 10235, 10236, 
    10242, 10243, 10244, 10245, 10246, 
    10247, 10248, 10249, 10250, 10251
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id", "idx_product_lang"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 16,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (10228,10229,10232,10233,10235,10236,10242,10243,10244,10245,10246,10247,10248,10249,10250,10251) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}