Note that there may be other solutions. Bombs are listed in fuse-length order.

Stop the clock
Push bomb 3 (longest fuse) to platform edge. You can use it to jump up on the platform.
Push bomb 1 to trigger
Push bomb 2 to moving plate
Start clock, let bomb 1 explode, then stop clock
Jump up on platform using bomb 3
Move bomb 2 to door
Start clock, let bomb 2 explode, stop clock
Jump up on platform using bomb 3, exit