You can use CURDATE()
SELECT CURDATE(); //2022-05-24
SELECT users.id, DATE_FORMAT(users.signup_date, '%Y-%m-%d')
FROM users
WHERE DATE(signup_date) = CURDATE()
In MySQL the CURDATE() returns the current date in 'YYYY-MM-DD' format or 'YYYYMMDD' format depending on whether numeric or string is used in the function. CURRENT_DATE and CURRENT_DATE() are the synonym of CURDATE()
SELECT NOW() AS DATETIME; //2022-05-24 15:38:58
SELECT NOW();
It returns current date and time.