SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    10127, 10128, 10129, 10145, 10160, 10166, 
    10167, 10170, 10171, 10172, 10173, 
    10174, 10175, 10176, 10177, 10178
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00039

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 (10127,10128,10129,10145,10160,10166,10167,10170,10171,10172,10173,10174,10175,10176,10177,10178) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}