Bolt with lock tightened very strong

[witje]

Safety bolts suck. I had to cut a wheel of a volvo because of this. I use only regular bolts or even better: nuts

Try using a torch, heat up the bolt until its glowing. That will free it up so you can use your tools to undo it.

[NielsE36]

If heating the bolt would fail too, I would recommend trying to drill the bolt to pieces.
Perhapes make some sort of mould made of wood to drill through, to prevent damage to the rims.