Why are there no indexes contained in the information_schema database?
Also the way the information schema tables is generated internally means that the entire table is generated before a single attempt at filtering is done on the table.
An index has no meaningful effect on information_schema tables.
So for performance considerations, don't overly use information_schema tables, there could be performance impacts on the entire system.
note: above refers to MySQL-5.7 and MariaDB information_schema. I haven't looked at the MySQL-8.0 implementatoin.