Composite key condition

Sure, try this

$checkExist = Daily::findFirst(
                [
                    'columns'    => 'ts',
                    'conditions' => 'ts = :ts: AND tds_id = :tdsId: AND tracking_id = :trackingId:',
                    'bind'       => [
                        'ts'         => $this->timeFrom,
                        'tdsId'      => $pair->tds_id,
                        'trackingId' => $pair->tracking_id,
                    ],
                ]
            );

Thank you David, but may be I wasn't clear enought. I understand I can use AND condition, but it may cause perfomance issues I thought... The main question "Is it possible to use model condition with composite key" or we can do it only via raw queries.

Btw EXPLAIN shows that there is no difference between your and my queries :) So I think this trivial solution will be ok.

mysql> EXPLAIN SELECT `ts` FROM `daily` WHERE (ts, tds_id, tracking_id) = ('2015-06-01 08:00:00', 17, 5133);
+----+-------------+-------+-------+---------------+---------+---------+-------------------+------+-------------+
| id | select_type | table | type  | possible_keys | key     | key_len | ref               | rows | Extra       |
+----+-------------+-------+-------+---------------+---------+---------+-------------------+------+-------------+
|  1 | SIMPLE      | daily | const | PRIMARY       | PRIMARY | 12      | const,const,const |    1 | Using index |
+----+-------------+-------+-------+---------------+---------+---------+-------------------+------+-------------+
1 row in set (0,00 sec)

mysql> EXPLAIN SELECT `ts` FROM `daily` WHERE ts = '2015-06-01 08:00:00' AND tds_id = 17 AND tracking_id = 5133;
+----+-------------+-------+-------+---------------+---------+---------+-------------------+------+-------------+
| id | select_type | table | type  | possible_keys | key     | key_len | ref               | rows | Extra       |
+----+-------------+-------+-------+---------------+---------+---------+-------------------+------+-------------+
|  1 | SIMPLE      | daily | const | PRIMARY       | PRIMARY | 12      | const,const,const |    1 | Using index |
+----+-------------+-------+-------+---------------+---------+---------+-------------------+------+-------------+
1 row in set (0,00 sec)

Ah, sorry. I think, that Phalcon does't support composite key syntax.

If you need that, you will have to override standard database abstraction layer, documentation can be found here https://docs.phalcon.io/en/latest/reference/db.html