This trophy is obtained by collecting all the Cortex tokens in Jaws of Darkness. Doing this will place Crash in the Cortex bonus round for the level. Once in the bonus round complete the sequence and collect the key at the end to receive the trophy. Here are the locations of the three Cortex Tokens:

1. Right before the first checkpoint box, you will notice a pile of 3 boxes right beside it. The bottom "?" box houses the first Cortex Token.
2. Shortly after the second checkpoint, you will notice a snake pop out of a hole with some boxes on the following platform. Do not spin into the snake! If you do, then you will send the snake flying into the following T.N.T. box and cause the following boxes to explode and destroy its contents (including the Cortex Token). Instead, jump on the snake to kill it. The token is in the far right "?" box on the following platform.
3. Right after you collect the second token, progress to the left and you will see three lone Wumpa Fruit over what seems to be a bottomless pit. There are actually invisible platforms over that bottomless pit. Just keep walking left. From there, you will see the Cortex Bonus Room Teleporter. Right beside said teleporter are a set of boxes and the top left "?" box houses the final token.

There is a total of 2 keys in the game. If you'd like to see a visual guide on the locations of Crotex's Tokens in this level, then they can be seen in the 'Jaws of Darkness' portion of the video in  The Ultimate Gem Path. (Starts at 1:14:58).