Get Data From WordPress user meta table

I’ve to fetch user data from the usermeta table in wordpress database.fields of the usermeta table are

umeta_id
user_id
meta_key
meta_value

and sm=ome of the meta keys are first_name , last_name I want to retrieve data from the table based on this meta_key. I am getting data from the user main table using the query given below

$args  =  array(
    'blog_id'      => $GLOBALS['blog_id'],
    'role'         => '',
    'meta_key'     => '',
    'meta_value'   => '',
    'meta_compare' => '',
    'meta_query'   => array(),
    'include'      => array(),
    'exclude'      => array(),
    'orderby'      => 'ID',
    'order'        => 'ASC',
    'offset'       => '',
    'search'       => '',
    'number'       => '',
    'count_total'  => false,
    'fields'       => 'all',
    'who'          => ''
 ); 
// Create the WP_User_Query object
$wp_user_query = new WP_User_Query($args);

what to write if i need the first_name of the user with user id 1

please help me some one