Blacksmith hit it on the head intensity is the key to length of your workout. For example, if I am short on time, I may use strip sets for a fast and hard workout. Using bench as an example, I will warm up with 2-3 sets then put about 80% of max on the bar in smaller weights for half of it. (say your doing 225, put on your standard 135, then make the rest up in 5 and 10 pound plates) I will rep out, IMMEDIATLY strip a plate off each side, and rep that out, continuing until I was down to the 135. Now I am done with chest. Using strip sets, rest pause, etc will hit your muscles hard and fast.
OTOH I also do GVT on occasion, which is lower poundages, and 10 sets os 10 using the same weight. If I am doing GVT the entire workout may take an hour and a half.
As you advance as a lifter, you learn to have more and more intense workouts, and therefore need to cut the time down as well as the sets in many cases. It is just something you learn as you go along.