As per this example, you can see the results of the "mogrify" after the statement has been executed.
import MySQLdb
conn = MySQLdb.connect()
cursor = conn.cursor()
cursor.execute('SELECT %s, %s', ('bar', 1))
print cursor._executed
Which will print
SELECT 'bar', 1
Moreover, you don't need to use mogrify before execution
query = cursor.mogrify('SELECT %s, %s', ('bar', 1))
cursor.execute(query)
You can simply do the following
cursor.execute('SELECT %s, %s', ('bar', 1))
This will work across all DBs that use the Python DB API