SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    22223, 22224, 22225, 22226, 22227, 22228, 
    22229, 22230, 22231, 22232, 22233, 
    22234, 22235, 22236, 22237, 22238
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00069

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 (22223,22224,22225,22226,22227,22228,22229,22230,22231,22232,22233,22234,22235,22236,22237,22238) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}