That would be about 20-25 minutes in a freezer. If you put it in a bucket of ice, that would halve that time. If you put water in that ice, itd be cold (+- 5c) enough to drink in about 4-6 minutes, if you put salt in that water, youd reduce the chill time to just over 2 minutes. Agitating the can in the water, rolling it around, reduces the chill time even more.
The fastest possible way is to grab a CO2 fire extinguisher and unload that sucker on the can.
Whatever you do, do NOT bury the can in sand, pour gasoline on the sand and set the sand on fire. That wont do anything.
This is all empirically gained evidence, not third party.
Adam Savage of Mythbusters explains the fastest way to chill a warm can of coke.