Query would run directly on MySQL but not through PHP

I have a simple MySQL query

select * from tutor where verified = 0 and alert_by < '2015-08-05' LIMIT 0,1

Now, running this directly through phpMyAdmin provides the desired results, however, when this query is being executed through a set of PHP statements, it doesn't return anything. Below is my code in PHP

$this_date = date("Y-m-d");

$query = "select * from tutor where verified = 0 and alert_by < '$this_date' LIMIT 0,1";

$contact = mysqli_query($conn, $query);
$row = $contact->fetch_array(MYSQLI_ASSOC);

However, the $row is empty, I can't seem to figure this out. I know this seems trivial, but its a little annoying.

Note: Removing "and alert_by < '$this_date'" from the query, works fine.

via Chebli Mohamed