MCO is a crap shoot. Sometimes there's not a soul around at 4am, other times they are across the entire atrium there.
The bad news - no priority security lanes.
The good news - it all moves pretty quickly and MCO is one of the better airports for getting crowds through.
The Delta ABSOLUTE MINIMUM for checked bags at MCO is 45 minutes. So if you decide to check, remember that. With no bags to check I would say an hour (4:30) before is safe, but that's being at the security line, not driving around one of the parking lots.
Good luck, enjoy the Mouse,