get_keys() on large site is slow

Hi, the function get_keys() on utilities has this query:

SELECT DISTINCT meta_key from {$wpdb->postmeta}

which is hitting the database pretty hard on a very large site with a huge database.

# Query_time: 13.394848  Lock_time: 0.000044 Rows_sent: 1224  Rows_examined: 800512
SET timestamp=1519137888;
SELECT DISTINCT meta_key from wp_postmeta;

Is there a fix for this? or a way to optimize the query?