SELECT 
  product_id, 
  feature_short_desc 
FROM 
  cscart_ab__short_desc_from_features_values 
WHERE 
  product_id IN (
    20941, 20942, 20943, 20944, 20945, 20946, 
    20947, 20948, 20949, 20950, 20951, 
    20952, 20953, 20954, 20955, 20956
  ) 
  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 (20941,20942,20943,20944,20945,20946,20947,20948,20949,20950,20951,20952,20953,20954,20955,20956) and cscart_ab__short_desc_from_features_values.lang_code = 'en'"
    }
  }
}