title: What does {expires_at: 0} mean is debug_token response?
body: <p>Here is a response to my attempt to validate user's <code>access_token</code>.</p>
  
  <pre><code>{
      "data": {
          "app_id": 409277239141609,
          "is_valid": true,
          "application": "Les \u00e2mes vagabondes",
          "user_id": 100003752867359,
          "issued_at": 1353410808,
          "expires_at": 0,
          "scopes": ["create_note", "email", "manage_pages", "photo_upload", "publish_actions", "publish_stream", "share_item", "status_update", "user_birthday", "user_interests", "user_likes", "user_photos", "video_upload"]
      }
  }
  </code></pre>
  
  <p>It says that the <code>access_token</code> is valid, though does not give the <code>expires_at</code> timestamp. How do I get the <code>expires_at</code> then?</p>