It's really important that you actually consider the following:
1. Why are you doing "cardio"?
2. Is your choice of "cardio" work appropriate to the desired result?
Lots of people cite running as the king of cardio exercise - unfortunately it's pretty far removed from the demands of MMA competition.
Try five minute rounds of bodyweight drills or shorter duration sprints.
Example: 1 minute Squats, 1 minute push-ups, 1 minute skipping, 1 minute box jumps, 1 minute sit ups. Or any combination of drills.