SELECT 
  link_id, 
  link_href, 
  section_id, 
  status, 
  position, 
  link_type, 
  description, 
  object as link 
FROM 
  cscart_sitemap_links 
  LEFT JOIN cscart_common_descriptions ON cscart_common_descriptions.object_id = cscart_sitemap_links.link_id 
  AND cscart_common_descriptions.object_holder = 'sitemap_links' 
  AND cscart_common_descriptions.lang_code = 'ja' 
WHERE 
  section_id = 5 
ORDER BY 
  position, 
  link

Query time 0.00109

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "cscart_sitemap_links.position, cscart_common_descriptions.object",
      "temporary_table": {
        "table": {
          "table_name": "cscart_sitemap_links",
          "access_type": "ALL",
          "rows": 8,
          "filtered": 100,
          "attached_condition": "cscart_sitemap_links.section_id = 5"
        },
        "table": {
          "table_name": "cscart_common_descriptions",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "108",
          "used_key_parts": ["object_id", "lang_code", "object_holder"],
          "ref": [
            "cscart_purchase_fl_com.cscart_sitemap_links.link_id",
            "const",
            "const"
          ],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(cscart_common_descriptions.object_id = cscart_sitemap_links.link_id and cscart_common_descriptions.object_holder = 'sitemap_links' and cscart_common_descriptions.lang_code = 'ja')"
        }
      }
    }
  }
}