When I was doing SS, and got close to stalling, squats would take me thirty minutes, minimum. Remember, it's not a race, not about cardio, not about body building. Rip says take up to ten minutes between sets. So, for three work sets, that's, mmm, 3x10, uh, thirty minutes.
It's maths bitches.
But, if you're not working for strength, it should take less.
Now, on 5/3/1, squats take me about twenty five minutes. That's body weight warm up, five reps with the bar, five with 95#, five with 135, five with 185, then three work sets - but I'm old, and a pussy.
EDIT: I do band pull aparts between sets.
So, if you're not old, and not a pussy, less than thirty minutes.