search.php

 $params = [
            'index' => 'registrations',
            'type' => 'event_db',
            'body' => [
                'query' => [
                    'bool' => [
                      'filter'=>[
                          [
                              'query_string' => [
                                  'query' => $str,
                                  'fields'=> ['name', 'lastName', 'email', 'ticket_codes', 'ticket_hashes',  'accessCode']
                              ],
                          ],
                          [
                              'term' => [
                                  'event_id' => 'ev_' . $event->id
                              ]
                          ]
                      ]
                    ],
                ],
            ]
        ];
        
        return $this->_client->search($params);