do_pings cron bloating my database

I was taking a look at my database today, for an unrelated reason, and noticed that I have 752 instances of a wp cron scheduler for do_pings, and 543 instances of a wp cron scheduler for sm_ping. I unserialized the cron, and here is an example of each:

[1425757478] => Array
    (
        [do_pings] => Array
            (
                [40cd750bba9870f18aada2478b24840a] => Array
                    (
                        [schedule] =>
                        [args] => Array
                            (
                            )

                    )

            )

    )

[1428029649] => Array
    (
        [sm_ping] => Array
            (
                [40cd750bba9870f18aada2478b24840a] => Array
                    (
                        [schedule] =>
                        [args] => Array
                            (
                            )

                    )

            )

    )

[1428032540] => Array
    (
        [sm_ping_daily] => Array
            (
                [40cd750bba9870f18aada2478b24840a] => Array
                    (
                        [schedule] => daily
                        [args] => Array
                            (
                            )

                        [interval] => 86400
                    )

            )

    )

I usually a stickler for keep the database as clean as possible, and this seems like an enormous bloating. What can I do about this? I would ideally like to get rid of all of this, but is it actually doing anything useful?