Work fewer hours, definitely.
If you really can't, more important than doing 1h of exercises is to spread movement over your day. In this regard, Deskbound will probably help you amazon.com/Deskbound-Standing-Up-Sitting-World/dp…
This is for you to at least be functional/healthy, not ripped.
If you can squeeze a few more minutes in your day, learn to do body weight exercises. Grab a book like amazon.com/You-Are-Your-Own-Gym/dp/0345528581 (it's ok) and start doing them at home, when you can.