Hello @kartik,
Make sure you have already added the csrf token to your form with {{ csrf_field() }} like the OP.
If you have your session driver set to file:
May have something to do with the storage_path not being writable. This is where it stores session data regarding tokens if you're using file based sessions. The can be verified with is_writable(config('session.files'))
For the OP, the session driver was set to array. Array is for testing only. Since data is not persisted, it will not be able to compare the token on the next request.
Hope this is helpfull!!
Thank You!!