Is Keystone Group of Institutions a good choice for MBA?

No, why you are not considering Jaipur. The college you asking for is not even good enough for its core courses i.e B.Tech. The college which is worth spending money and time is BITS-Pilani. Try CAT exam and then apply for BITS-Pilani.

Before Selecting MBA, try to research about various MBA colleges. If you find one which is within your budget, infrastructure, placements, etc. is upto your expectation, go for it. We cannot tell whether a college is good choice or not rightly except in the case of some reputed colleges like IIMs, X