Instructions
Go to your TNT trap.
Locate the redstone wire on the ground. Assuming you have not hidden the wiring, in which case you must dig through the block above the wiring, this is always between the TNT block and the trigger block: a lever or a pressure plate.
Tap the left mouse button while hovering your cursor over the redstone wire. Just one tap will be enough to break the wiring, which disarms the trap.