I concur with MikeLaw - I have been on a few flights where the flight time is 3:24 and they still serve a meal. As for a flight that is out of "meal time" my experience (based upon an upcoming redeye) is that if the flight is at a time not within the parameters for meals the meal will be listed as "none" (see below).

404 10:25 PM SFO 6:11 AM CLT 4h 46m None A321 First (O) 1C