SQL: Unix Timestamp entrys with Zero - php

Question

i misunderstand why my query gives me entrys with an Timestamp of 0. Can anyone say me what im doing wrong?
Query:
SELECT
*
FROM
`changes`
WHERE
`time_from`>=1393628400
AND
`time_to`<=1394838000
AND
`area`='USERNAME'
ORDER BY
`time_from` DESC,
`time_to` DESC
PHP
$time_from = (isset($_POST['time_from']) ? strtotime($_POST['time_from']) : null);
$time_to = (isset($_POST['time_to']) ? strtotime($_POST['time_to']) : null);
if(empty($time_from) && empty($time_to)) {
/* Do Nothing */
} else {
if(!empty($time_from) && $time_from > 0 && !empty($time_to) && $time_to > 0) {
$query = sprintf(' `time_from`>=%d AND `time_to`<=%d', $time_from, $time_to);
} else if(!empty($time_from) && $time_from > 0) {
$query = sprintf(' `time_from`>=%d', $time_from);
} else if(!empty($time_to) && $time_to > 0) {
$query = sprintf(' `time_to`<=%d', $time_to);
}
$results = $wpdb->get_row(sprintf('SELECT COUNT(*) AS `count` FROM `%sarea_changes` WHERE%s AND `area`=\'%s\'', $wpdb->prefix, $query, $user->user_login));
$count = $results->count;
if($count < 10) {
$position = 0;
$has_more_pages = false;
}
$pages = ceil($count / $max_rows);
$query = sprintf('SELECT * FROM `%sarea_changes` WHERE%s AND `area`=\'%s\' ORDER BY `time_from` DESC, `time_to` DESC', $wpdb->prefix, $query, $user->user_login, $position, $max_rows);
print $query;
$entrys = $wpdb->get_results($query); // LIMIT %d, %d
}
POST Data:
time_from is 01.03.2014 and time_to is 15.03.2014
But i get following entrys (see the time_to), why is that 0 that dont match my Query?
Screenshot:
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