driving fine, no problems, get in to go to the store, it won't fire up. The engine has no clicking sounds and the battery seems to be fine.
1999 Lexus LX470 will not fire up on 1999 Lexus LX470
It could be a failed starter (it's in an awkward place under the intake manifold), I have see the mechanical part of the ignition switch fail (key rotates in switch but doesn't start), it could be many things but without proper diagnostic tests anything is only a guess.
open large fuse box in engine compartment, while someone is cranking the engine over tap on all the relays (black 1.25" sq things in fuse box) it should start