SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    23119, 23120, 23121, 23122, 23123, 23124, 
    23125, 23126, 23127, 23128, 23129, 
    23130, 23131, 23132, 23133, 23134
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00421

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 (23119,23120,23121,23122,23123,23124,23125,23126,23127,23128,23129,23130,23131,23132,23133,23134) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}