Wow! Looks like Key telugu 2011 is not available on any streaming services in the world!

Key is a 2011 Telugu psychological thriller produced by Sukumar Reddy for Dream Theater Entertainments[2] and directed by Nagendra Prasad.[3] Jagapati Babu plays the lead role, and the music was composed by Vijay Kurakula.[4] The film is a remake of the English film Exam.[5][6]