SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    10373, 10380, 10382, 10383, 10395, 10400, 
    10401, 10402, 10403, 10404, 10405, 
    10406, 10407, 10410, 10411, 10417
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00034

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 (10373,10380,10382,10383,10395,10400,10401,10402,10403,10404,10405,10406,10407,10410,10411,10417) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}