This SQL-Code returns a List of all Wordpress posts with a Yoast-SEO Fokus Keyword and the URL of the post. You Can download it as CSV (in MySQLAdmin).

wordpress-yoast-fokosword-sql.sql

SET @domain="https://www.example.org/";
SELECT meta.post_id AS 'PostID', meta.meta_value AS 'Fokus Keyword', post.post_title AS 'Title', Concat(@domain, post.post_name) as "URL"
	FROM wp_postmeta AS meta, wp_posts as post
	WHERE meta.meta_key = '_yoast_wpseo_focuskw'
		AND post.ID = meta.post_id
		AND post.post_status = 'publish'
	ORDER BY post.post_date ASC