Custom Post Type meta value is being saved in array, instead of just the string (as value)

So, this is how WordPress is saving my CPT meta:

 array(8) {    
 ["product_id"]=> array(1) { [0]=> string(10) "abcdefg987" }  
 ["end_date"]=> array(1) { [0]=> string(10) "02-02-2015" }  
 } 

But I want it to be like this:

 array(8) {    
 ["product_id"]=>  "abcdefg987" ,
 ["end_date"]=>  "02-02-2015"   
 } 

So, is it possible ?

---

Here is some of my code:

to save:

update_post_meta($post_id, "end_date", $_POST["end_date"]);

The meta box:

global $post;
$custom = get_post_custom($post->ID);  
$end_date = $custom["end_date"][0]; // <- this was an old hack to this problem  
<p><label>End Date:</label><br />  
<input name="end_date" value="<?php echo $end_date; ?>"></input></p>

---

What I really want to do ?

What I need is to get the Post (custom) with the 'end_date' greater than today. So, I have a meta_query, but doesn't work, cause also shows me the posts with 'end_date' < today, so I thought is because it get its values in the array, and not just the values, here is the code:

$args = array(
    'post_type' => 'myEventCPT',
    'meta_query' => array(
            array(  'meta_key' => 'end_date',
                    'value' => date("m-d-Y"), // Set today's date 
                    'compare' => '>=', 
                    //'type' => 'DATE'
            )
    )
);  
$my_event_post = get_posts( $args );