You can change the time per generation/batch during the simulation from the pause screen. The pause button is at the bottom of the screen.
However, please note that lowering the simulation time per generation doesn't make the creatures evolve faster. It's not equivalent to a speedup slider or anything similar. It's just the amount of time you give the creatures to show their behaviour before the algorithm goes in and has to decide which ones are better than others. If that time is too short, the algorithm has no proper way of being able to tell which creatures perform better and at that point selection becomes pretty much random. So setting that number too low (in this case 1 sec) will definitely ruin the simulation and you shouldn't expect any progress at all.
I would strongly recommend not setting the value to anything significantly less than 10 sec.
