How to optimize information schema table in mysql?
Information Schema is not like other databases:


  They are actually views, not base tables, so there are no files
  associated with them, and you cannot set triggers on them. Also, there
  is no database directory with that name.


source - https://dev.mysql.com/doc/refman/5.7/en/information-schema.html

and not a lot of ways for optimise queries over it
there are few recommendations (very standard for any queries)

https://dev.mysql.com/doc/refman/5.7/en/information-schema-optimization.html

recommendations is really standard and in Your case - with count(*) not help.