SELECT 
  product_id, 
  feature_short_desc 
FROM 
  cscart_ab__short_desc_from_features_values 
WHERE 
  product_id IN (
    21309, 21310, 21311, 21312, 21313, 21314, 
    21315, 21316, 21317, 21318, 21319, 
    21320, 21321, 21322, 21325, 21326
  ) 
  AND lang_code = 'ru' 
  AND storefront_id = 1

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_ab__short_desc_from_features_values",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 32,
      "filtered": 100,
      "attached_condition": "cscart_ab__short_desc_from_features_values.storefront_id = 1 and cscart_ab__short_desc_from_features_values.product_id in (21309,21310,21311,21312,21313,21314,21315,21316,21317,21318,21319,21320,21321,21322,21325,21326) and cscart_ab__short_desc_from_features_values.lang_code = 'ru'"
    }
  }
}