SELECT 
  product_id, 
  feature_short_desc 
FROM 
  cscart_ab__short_desc_from_features_values 
WHERE 
  product_id IN (
    21037, 21038, 21039, 21040, 21041, 21042, 
    21043, 21044, 21045, 21046, 21047, 
    21048, 21049, 21050, 21051, 21052
  ) 
  AND lang_code = 'en' 
  AND storefront_id = 1

Query time 0.00024

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 (21037,21038,21039,21040,21041,21042,21043,21044,21045,21046,21047,21048,21049,21050,21051,21052) and cscart_ab__short_desc_from_features_values.lang_code = 'en'"
    }
  }
}