At Advanced Training, we have gotten our lifting sessions down to under an hour.
This includes the warm-up, the cool-down, the stretching, etc.
One of the ways we are able to do this is through "combo" exercises.
A "combo" exercise is one in which multiple movements are performed at the same time in an effort to work multiple body parts.
While these movements should never replace your "big" lifts (like bench, deadlifts, or squats), they do work very well as "assistance" exercises.
Below is a video of one of our athletes performing bicep curls + shoulder presses on a decline bench.
Not only is he working his biceps and shoulders, he is also working his core via the stabilization required to hold himself in that position.
If you have no interest in spending five hours in the gym, try incorporating these types of lifts into your training program.