ElasticSearch without response data in PHP

This is my mapping:

$ curl -X GET -k -u elastic:elastic “http://127.0.0.1:9200/_mapping”

{"photobank":{"mappings":{"properties":{"id":{"type":"long"},"title":{"type":"text","fields":{"keyword":{"type":"keyword","ignore_above":256}}}}}}}
I inserted test data like title: “aaa” and “bbb”.
But when I search I heva no response from ES:

$params = [
                    'index' => 'photobank',
                    'body'  => [
                        'query' => [
                            /*'match' => [
                                'title' => 'aaa'
                            ],*/
                            'bool' => [
                                'must' => [
                                    'match' => [
                                        'title' => 'aaa'
                                    ]
                                ],
                            ]
                        ]
                    ],
                ];
$response = $client->search($params);

$response has status 200 but nothing more. Where are result data or is my query wrong?