Hello,

You have scored a good score in Gate and have a good cgpa in btech it will easily get you in top iit as there cutoff is generally between 600-650 if we go according to previous year 

I am sharing you a link which will help you to get notified in which IIT you want to pursue your M.Tech 

https://engineering.careers360.com/articles/gate-cutoff-for-iits

Hope  you will find your answer in this link and will land up in a  good IIT college for your M.Tech