I fully agree with Erel about the way how to set it as "read".
Just only want to add that even you can set a log to be "read", but it seems that the missed call notification of that call log can still stay on the notification bar (at least for my device, but not for others, so I guess that it depends also on the Android version), in other word, it can create a strange situation to user as the call list contains no new log (no unread) while the user still see missed call notification being displayed. You have to be aware of this.