Researching more, I got it to work with the following code
$post = array(
'posts_per_page' => 10,
'post_type' => 'post',
'tax_query' => array(
'taxonomy' => 'category',
'field' => 'slug',
'terms' => 'category-1'
),
'meta_query' => array(
array(
'key' => 'custom-key',
'value' => array(1,100),
'compare' => 'BETWEEN',
'type' => 'NUMERIC'
)
),
'meta_key' => 'custom-key',
'orderby' => 'meta_value',
'order' => 'ASC'
);
Reference: http://www.wphub.com/use-meta_query-query-posts-postmeta/