Do an if to see if time is over 60 minutes and if so assign it a class with a different background color. Since you didn't clarify I'm going to assume you are using unix timestamp time()
.
$currTime = time();
if($result) {
while($row = mysqli_fetch_assoc($result)) {
$calc = $currTime - $row['TimeStamp'];
if($calc > 3600){
$rowClass = "oldOrder";
} else {
$rowClass = "normalOrder";
}
echo '';
echo $row['OrderNumber'] . '';
echo ' | ';
echo $row['Destination'] . '';
echo ' | ';
echo $row['Location'] . '';
echo ' | ';
echo $row['Status'] . '';
echo ' | ';
echo $row['TimeStamp'] . '';
echo ' |
';
}
Then add CSS to define the two classes
.oldOrder{
background-color: #ccc;
}
.normalOrder{
background-color: #fff;
}