You have to get one yourself.If you see one online you will most likely not be able to use it because it has already been redeemed by someone.
By planing and winning the Key Quest game
If you login to neopets, use the top navigation menu where it says GAMES. A window should appear when you hover over Games, and Key Quest is one of the options. An alternative is to go to games and search for Key Quest (though it is usually on the main Games page). Another alternative, this will take you directly to the main page: http://www.neopets.com/keyquest/redeem.phtml Once you arrive on the main Key Quest page you will see a box on the right-hand side of the page where you can enter your Key Quest redemption codes.
The answer was Key Quest.
Some real life items (such as Neopets plushies) can be purchased to redeem special codes that allow you to add new tokens (Keyquest game pieces) to your collection case and include exclusive virtual items as well.
buy a plushie for real
You can purchase different character game pieces with neocash and redeemable codes. Yes, it is lame but you can't buy them with neopoints.
I got my key quest tokens from playing various games like the recent daily dare challenges :) check out my collection.... Starsong001
You must buy a certain neopets plushie, or other merchandise that gives you a code usually on a tag. Go to the Neopets merchandise page to find a listing of stores to get these items. You can also buy the items or codes online, which is only recommended if bought from a secure, reputed company because you may be scammed of your credit card info, or something else like that.
Find all the pieces of the pepet lab. map. This can be random OR, you can get a random one in key quest.
You have to get one yourself because if someone tells you a code they already probably used it.
if you mean the key quest tokens, there's a code for them on almost all neopets merchandise, including the burger king neopets plushies, but i think burger king isn't doing it anymore.
Lots of work, couple of random events and lots of work. Key Quest helped me a lot. Also a lot of work...