Indexes in primary key columns

Question

I know that each case is a case, and that there are no ready-made rules on the creation of indexes. In my case, considering that the primary key of each table of my bank is used in wheres of my bank inquiries, should I create an index for them? Or is the field defined as a primary key already considered by default as an index? This is because, in Phpmyadmin, when I create the index in the column already inserted as the primary key, there is the message that there are equal indexes for the same column, something like this.

Answer 1

In my case, considering that the primary key of each table of my bank is used in the wheres of my queries to the bank, I must create an index for them?

Primary key indication automatically creates an index for it. Nothing else needs to be done.

Check if you are creating any unnecessary index.