SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    22287, 22288, 22289, 22290, 22291, 22292, 
    22293, 22294, 22295, 22296, 22297, 
    22298, 22299, 22300, 22301, 22302
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00033

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 (22287,22288,22289,22290,22291,22292,22293,22294,22295,22296,22297,22298,22299,22300,22301,22302) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}