Elasticsearch find by qyery and exact match parameters

There is some index, that consists of such fields:

'index' => 'material',
'type' => 'post',
'id' => $post->id,
'body' => [
    'material_title' => $post->material_title,
    'material_body' => $post->material_body,
    'region' => $post->region_code,
]

After that i have 2 input parameters: text query - for example "all good news today" and region code.

The search should be performed on 3 fields (material_title,material_body,region), one of which (region code) must be exactly the same.

My search params now:

$query = [
            'multi_match' => [
                'query' => $request->q,
                'fuzziness' => 'AUTO',
                'fields' => ['material_title', 'material_body'],
            ],
        ];

    $parameters = [
        'index' => 'material',
        'size' => 20,
        'from' => 0,
        'type' => 'post',
        'body' => [
            'query' => $query
        ]
    ];

Can u give me some examples or advice how to realize this logic? Thanks!

via Chebli Mohamed