The limitation is thickness of the Rad itself.
As a 240mm it can only fit in the front of the case.
The limitation is 50mm without fans, as per
http://www.coolermaster.com/case/mid-tower/masterbox-lite-5-rgb/
Looking at the packaging of the H100x you'll see here:
https://youtu.be/5B7-DABz5Rk?t=38
The rad thickness is only 27mm.
It'll fit just fine