salida.txt

MariaDB [login]> SELECT usuarios.id, usuarios.correo,
    -> (SELECT COUNT(*) FROM intentos_usuarios WHERE id_usuario = usuarios.id)intentos_fallidos
    -> FROM usuarios;
+----+---------------------+-------------------+
| id | correo              | intentos_fallidos |
+----+---------------------+-------------------+
|  1 | parzibyte@gmail.com |                 2 |
|  2 | luis@gmail.com      |                 1 |
+----+---------------------+-------------------+
2 rows in set (0.000 sec)

MariaDB [login]>