Programmatically defines the SearchWP license key so I can be added in wp-config.php or elsewhere. see https://searchwp.com/documentation/hooks/searchwp-license-key/
Place mu-searchwp-license.php in /wp-content/mu-plugins
Add your private license key to wp-config.php:
define( 'SEARCHWP_LICENSE_KEY', '0123456789abcd0123456789abcd01234' )