No matter what kind of locks you use, if a toddler tries to climb on the enclosure, that wire mesh is going to pull right out. I left an enclosure like that in my hall (empty) and the cat sitting on it collapsed the lid mesh. Not to mention, a kid could dump something into the tank trying to play. I would advise putting the entire thing somewhere the child cannot get to.
When my kids were little, I had a big double 50 gallon fish tank with snakes in it, much stronger wire mesh lids, and the outlet was behind that so they couldn't reach cords. Heat was under tank heaters sandwiched between the stand and tanks. I don't know where your outlets are if you could get a heavy stand to accomplish the same thing, and buy a new lid that just goes over the top of the existing one with clips on the sides. The lights certainly have to go or be placed in a locking canopy, the kid can move them around and probably burn themselves. [edit: just in case it's not obvious, if you do away with the lights, you need to get a different type of heater]
I know zilla makes a lid that instead of window screen is thicker metal mesh.