If you have received two Keys then you can install them on two different machines (Servers) 1 -DEV & 2- PROD
For multi node scenario you can use a single license like i was using and create virtual proxies to support DEV/QA/PROD environments.
There is no restriction (?) on how many nodes you can attach to a single license. You can find that in your LEF from QMC.
This will be helpful to look at.