Add search Value to wp_list_table pagination

I solved my issue by passing the page variable as a hidden field:

<form method="get">
    <input type="hidden" name="page" value="<?php echo $_REQUEST['page'] ?>" />
    <?php
    $this->customers_obj->prepare_items();
    $this->customers_obj->search_box('Search', 'search');
    $this->customers_obj->display(); ?>
</form>