SELECT * From tbl 
WHERE my_time > 'UNIX_TIMESTAMP( '2018-04-21' ) '
order by my_time

SELECT * From tbl 
WHERE my_time BETWEEN  UNIX_TIMESTAMP( '2018-04-01' )  AND UNIX_TIMESTAMP( '2018-04-30' )
order by my_time

SELECT SUM(amount) , DATE(my_time) as Date FROM tbl
group by Date
order by Date

CREATE TABLE `tbl` (
  `id` int(64) NOT NULL AUTO_INCREMENT,
    `user_id` int(64) DEFAULT NULL,
  `status_id` int(2) DEFAULT NULL,
    `start_time` timestamp NULL DEFAULT NULL COMMENT 'Start from our panel',
 ) ENGINE=MyISAM AUTO_INCREMENT=22 DEFAULT CHARSET=utf8;

INSERT INTO tbl ('id', 'user_id', 'status_id', 'start_time')
VALUES(1 , 10, 1, '1378283588')