need to select first item in meta_value array to sortby

Is it possible to select the first item in an array like below to sortby? I am need to sort by application type, but needing to sort it by just the first item in the array. Below is what I am using and hopefully something like it would? Hope I’m making sense. Really would appreciate the help!

$args = array(
// ‘relation’ => ‘AND’,
‘cat’ => 5,
‘post_type’ => ‘post’,
‘post_status’ => ‘publish’,
‘posts_per_page’ => -1,
‘meta_query’ => array(
array(
‘key’ => ‘floor_type’,
‘value’ => $floor_type
),
array(
‘key’ => ‘stack_type’,
‘value’ => $stack_type
),
array(
‘key’ => ‘plumbing_opening’,
‘value’ => $plumbing_opening
)),
‘meta_key’ => ‘application_type’,
‘orderby’ => reset($meta_value),
‘order’ => ‘ASC’
);
$posts = query_posts($args);