GMAT is the only criteria for selection at ISB. The admission team checks your complete profile in terms of leadership potential, teamwork, quality of experience, etc. They also look for diversity.
The chances of a person getting admission in ISB with a GMAT score of 570 is very much hypothetical. In reality, something like this stands for an exception only. On average you will need a Mean GMAT score of 710 in order to get admission at ISB.
It’s necessary that you will be able to communicate with international professors and colleagues on and off-campus. You should be able to participate and add value to the class case studies and curriculum. Additionally, they also check if you can be able to cope up with the intense one-year program. This is where GMAT and grades fit in - it’s almost a benchmark of the academic capabilities.
Your profile has to satisfy all of these criteria for your admission. It would be a worthwhile effort to interact with ISB alumni for an evaluation of your complete profile for applying to ISB. You should be well aware as to why are you choosing to pursue MBA at the current juncture in your career.