转换expires_at文件从调试令牌在Facebook c# sdk

你好，我得到了debug_token的JsonObject，我需要知道什么是expires_at/issued_at(什么是dataType)以及如何将其转换为C#的DateTime。

简单地说，我需要知道Facebook是什么意思expires_at。是死亡时间(秒/分)还是正确的时间格式(DateTime)
我正在使用Facebook C# SDK

{
    "data": {
        "app_id": *********,
        "is_valid": true,
        "application": "MyApp1",
        "user_id": *********,
        "issued_at": 1367606488,
        "expires_at": 1372790488,
        "scopes": [
            "create_note",
            "manage_notifications",
            "photo_upload",
            "publish_actions",
            "publish_stream",
            "read_stream",
            "share_item",
            "status_update",
            "user_about_me",
            "user_photos",
            "video_upload"
        ]
    }
}