Fill in two fields (Form-input) with linked selection

Personal I have a problem, I find myself in the following situation

I have a product batch registration form, which in practice it searches for a product already registered, but I need to expand this batch register, which in addition to searching the product, it will fetch the quantity of validity months of this product.

In my controller it already works this way

$arrayProdutos = $this ->Produto->find('all',[
            'fields' => ['pro_id','pro_codigo_id', 'pro_descricao', 'pro_qtd_validade'],
            'conditions' => ['pro_situacao =' => 'A', 'pro_classes_id ='=> '1'],
            'order' => ['pro_descricao' => 'ASC']
        ]);
        $listaProdutos = [];
        $mes = [];
        if(!empty($arrayProdutos)){
            foreach($arrayProdutos as $key => $value){
                $listaProdutos[$value['Produto']['pro_id']] = $value['Produto']['pro_codigo_id']. ' - ' .$value['Produto']['pro_descricao'];
            }
        }

Basically he is looking for the product and his entire column, and my product input only registers the "pro_id". How can I make it so that when this pro_id is selected, it looks for the "pro_qtd_vality" of this product, for another input?

NOTE: my input in the view

                                <div class="form-group">
                                    <?= $this->Form->input('lote_produto', 
                                    [
                                        'label' => 'Produto:',
                                        'options' =>$listaProdutos,
                                        'empty' => 'Selecione o Produto',
                                        'class' => 'form-control',
                                        'id' => 'produto',
                                        'type' => 'select',
                                        'required' => true,
                                        'title' => 'Selecione o Produto',
                                        'name' => 'lote_produto',
                                    ]);
                                    ?>
                                </div>

I need to create one more input for the validity, which searches the validity of that product that was selected.