If you have to use that particular tank, you could make a "harness" that would fit around it, and put a lock on that. It would not be foolproof however.You would end up building a wooden frame around the upper edge, and adding an hinged flap that would fold across the top, then locking that.
Easiest to get a All-Glass sliding lid tank. We always used small padlocks on ours, never any issues. Ours were locked for the same reason, keep people out, not to keep the snake in.
Good luck