Meta Box plugin call un-needed query ?

Hi,
I have a performance problem in my website. Right now I'm finding a clue which can cause it.

I'm using Query Monitor and find that in every page, Meta Box plugin is querying one of my custom post type (which has about 2000 posts). I don't know what the relevancy of this query run for, but it started from 'init' function of meta-box plugin.

Would you mind to give me a clue how can I find out the way to minimize or probably erase this query?

Here is the query:

SELECT xxxxxx_posts.*
FROM xxxxxx_posts 
WHERE 1=1 
AND xxxxxx_posts.post_type = 'my_cpt'
AND ((xxxxxx_posts.post_status = 'publish')) 
ORDER BY xxxxxx_posts.post_date DESC

Below is the caller:

do_action('init')
wp-includes/plugin.php:453
RWMB_Core->register_meta_boxes()
wp-content/plugins/meta-box/inc/core.php:54
rwmb_get_meta_box()
wp-content/plugins/meta-box/inc/functions.php:281
RW_Meta_Box->__construct()
wp-content/plugins/meta-box/inc/meta-box.php:60
RW_Meta_Box::normalize_fields()
wp-content/plugins/meta-box/inc/meta-box.php:383
RWMB_Field::call()
wp-content/plugins/meta-box/inc/field.php:613
RWMB_Post_Field::normalize()
wp-content/plugins/meta-box/inc/fields/post.php:46
RWMB_Post_Field::query()
wp-content/plugins/meta-box/inc/fields/post.php:74
WP_Query->__construct()
wp-includes/class-wp-query.php:3336
WP_Query->query()
wp-includes/class-wp-query.php:3230
WP_Query->get_posts()
wp-includes/class-wp-query.php:2831