You cannot EXPLAIN procedures.
For example, if you compile the procedure update_orders and perform the following EXPLAIN, an error occurs because update_orders is not a valid SQL statement.
You should use EXPLAIN while building your procedures. You must extract the SQL text from the procedure body and EXPLAIN each of the individual statements. This can require modification of the procedure SQL text in some cases. For example, you might have to remove an INTO clause or add a USING request modifier to represent procedure variables and parameters.