Shortcode for latest -not expired- posts

Thanks, i got it now; indeed with meta_query.

function my_recent_posts_shortcode( $atts ) {
global $post;
$currenttime = current_time("mysql");

$args = array(
'post_type' => 'post',
'meta_query' => array(
    array(
        'key' => 'newsbox-date',
        'value' => $currenttime,
        'compare' => '>'
    )
)
);

$newsbox = new WP_Query( $args );

if ( $newsbox->have_posts() ) :
$list="<div class="newsbox-posts">";
while ( $newsbox->have_posts() ) : $newsbox->the_post();
$list .= '<h4>' . get_the_title() . '</h4>' . get_the_content() . '';
endwhile;
$list .= '</div>';
endif;

wp_reset_query();
return $list;

 }
add_shortcode( 'recent-posts', 'my_recent_posts_shortcode' );