Possible to get posts from multiple meta keys/values in a single query?

An easy query like the following should work for you:

<?php
$_query = new WP_Query( array(
        'post_type'         => 'post',
        'posts_per_page'    => -1,
        'post_status'       => 'publish',
        'meta_query' => array(
            'relation' => 'OR',
            array(
                'key'     => 'key1'
            ),
            array(
                'key'     => 'key2'
            ),
        ),
    ) );
?>

Note the 'relation'=>'OR' in meta_query.

More at:

• WP_Query – Custom Fields
• WP_Meta_Query