$keys = new stdClass;

$keys->keys =  array(

	array(
		'draw_id' => $last_draw_id,
		'uid' => $uid
	),
	array(
		'draw_id' => $next_draw_id,
		'uid' => $uid
	)

);


==============================
To Json -->
==============================

{"keys":[{"draw_id":385962,"uid":"12345"},{"draw_id":"385963","uid":"12345"}]}