Find tables without a primary key in MySQL

SELECT t.table_schema, t.table_name, t.engine, t.table_rows
  FROM information_schema.tables t
  LEFT JOIN information_schema.table_constraints c
         ON c.table_schema = t.table_schema
        AND c.table_name = t.table_name
        AND c.constraint_type = 'PRIMARY KEY'
 WHERE t.table_schema NOT IN ('mysql', 'information_schema', 'performance_schema')
   AND c.constraint_name IS NULL;