SELECT 
  a.attachment_id as 'attachment_id', 
  filename, 
  filesize, 
  category, 
  last_updated, 
  d.description as 'description' 
FROM 
  cscart_attachments as a 
  LEFT JOIN cscart_attachment_descriptions as d ON a.attachment_id = d.attachment_id 
WHERE 
  object_id = 65154 
  AND status = 'A' 
ORDER BY 
  d.description ASC

Query time 0.00399

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "d.description",
      "temporary_table": {
        "table": {
          "table_name": "a",
          "access_type": "ALL",
          "rows": 6837,
          "filtered": 100,
          "attached_condition": "a.object_id = 65154 and a.`status` = 'A'"
        },
        "table": {
          "table_name": "d",
          "access_type": "ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["attachment_id"],
          "ref": ["cscart_migrate.a.attachment_id"],
          "rows": 1,
          "filtered": 100
        }
      }
    }
  }
}

Result

attachment_id filename filesize category last_updated description
18601 MKT-0025_-_Barn_Light_Electric_Finishes_-_REV_A.pdf 2413279 4 1584115548 Barn Light Electric Finishes
18603 INS-0030_-_LED_Post_Mount_Fixture_Rev_G.pdf 300295 7 1693411460 LED Post Mount Light Installation Instructions
20738 MKT-0021_-_Optional_Accessories_-_REV_F.pdf 11539937 4 1682349295 Optional Accessories
18604 INS-0031_-_Post_-_Rev_E.pdf 79708 7 1584115596 Post Mount Burial Pole Installation Intructions
18600 SPS-0268_-_The_Seaside_Post_Mount_Collection_-_Rev_07.09.19.pdf 310925 1 1588616462 Seaside LED Single Post Mount Light