Prova questo :
DELIMITER $$
CREATE EVENT update_status
ON SCHEDULE
EVERY 2 MINUTE
DO
BEGIN
UPDATE
customer_group
SET
is_status = 0
WHERE
CURRENT_TIMESTAMP BETWEEN start_date AND end_date;
UPDATE
customer_group
SET
is_status = 1
WHERE
CURRENT_TIMESTAMP NOT BETWEEN start_date AND end_date;
END $$
DELIMITER ;