SELECT 
  product_id, 
  feature_short_desc 
FROM 
  cscart_ab__short_desc_from_features_values 
WHERE 
  product_id IN (
    20621, 20622, 20623, 20624, 20625, 20626, 
    20627, 20628, 20629, 20630, 20631, 
    20632, 20633, 20634, 20635, 20636
  ) 
  AND lang_code = 'en' 
  AND storefront_id = 1

Query time 0.00035

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": 16,
      "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 (20621,20622,20623,20624,20625,20626,20627,20628,20629,20630,20631,20632,20633,20634,20635,20636) and cscart_ab__short_desc_from_features_values.lang_code = 'en'"
    }
  }
}