Circuits! 5 min rounds with 5 min rest to begin with then gradually drop the rest down until you replicate the 5 min work/1 min rest of an actual fight.
Circuits don't have to be an all out slog from start to finish. It's good to mix in metabolic elements, strength, power and active rest.
This is a great example:
YouTube - Denis Kang training
You have the metabolic work on the airdyne, strength work on the pull-ups, power with the med ball, rest on the ladders/pummelling etc etc.
It goes from high intensity to low intensity so that you can regain some energy to perform your power exercises with near maximal effort. You dont have to use this exact circuit, just use this principle.
Also tabata type work on something like an airdyne or rower is good. I start guys off with 20 sec fast as you can/10 sec moderate pace and repeat that four times for a total of 2 mins work per set. They'll then get some rest and repeat the whole thing another 2 times. That's only 6 mins total work but it's a beast, trust me!
Once you get fitter just progress by adding another 30 sec of work to each set. So it might look something like this:
Weeks 1-2 - 3 sets of (20s fast/10s slow x 4)
Weeks 3-4 - 3 sets of (20s fast/10s slow x 5)
Weeks 5-6 - 3 sets of (20s fast/10s slow x 6)
Weeks 7-8 - 3 sets of (20s fast/10s slow x 7)
Weeks 9-10 - 3 sets of (20s fast/10s slow x 8)
I also like tabatas on the treadmill:
YouTube - Tabata Treadmill
Use a 15% incline and start slow, around 7mph. Then just build up the speed gradually as your progression. Take care though and make sure to lower yourself onto the treadmill gradually, ie almost dip yourself onto it.
MMA is an anaerobic sport so that's the system you want to be training. Your aerobic capacity will still be developed as a by product of the intense intervals.
No need for an hour of cardio. THis work only needs to be a supplement to the conditioning from sparring. If i do a 2 day per week program, i have one circuit day and one tabata day.