Loop through an array and find a dynamic key and set it to a variable

$total_keys = array_keys($total_rows);

	$fee_name = 'fee_';

	foreach ($total_keys as $key) {
		if (strlen($key) > 4 && substr($key, 0, 4) === 'fee_' ) {
			$fee_name = $key;
			break;
		}
	}