I go to the gym in the early morning but when I worked out over lunch it was:
00:00 - 00:05 Change into workout clothes
00:05 - 00:40 Work out
00:40 - 00:45 Shower (yes a shower only takes 5 minutes if you're not just relaxing under the water)
00:45 - 00:55 Back into work clothes
00:55 - 01:00 Back to the desk
Eat at the desk after the lunch break. If that's not practical you can cut the workout in half and have 20 minutes to eat which is rarely not enough time.
If you have a plan and don't waste time an hour is an exceptionally long time.
Typically, I do one heavy compound lift per day, mess around while I'm waiting for my coworker to finish running on the treadmill / lifting, and then do some ab exercises with her. We get some coffee from the cafe after that, and I eat my packed lunch at my desk.
Honestly, I really only need the shower on squat and deadlift days; bench and overhead press are comparatively light. I'm mostly in a holding pattern for fitness right now, as I work 12-hour shifts and then go to school full-time during the day. Once I'm not hating my life as much, I'll be able to do fitness that's a little more involved.
If you have a plan and don't waste time an hour is an exceptionally long time.