sugarquery

The SQL provided above is not valid, there is not a table known 'km'  and what is c.id = ".$active."?

Without access to your instance. We can only guess at the exact query syntax but it would be similar to

$query = new SugarQuery();
$query->from(BeanFactory::newBean('CX_TCO_Orders");
$query->join('contacts_cx_tco_orders_1_c', ['alias' => 'ct']);
$query->select('ct.contacts_cx_tco_orders_1contacts_ida');
$query->where()->equals('id', $active);

You can view the query generated using 

$sql = $query->compile()->getSQL();
$params = $query->compile()->getParameters();