variables table in D8?
In Drupal 8, you can find the equivalent in the config table.

mysql&gt; desc config;
+------------+--------------+------+-----+---------+-------+
| Field      | Type         | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| collection | varchar(255) | NO   | PRI |         |       |
| name       | varchar(255) | NO   | PRI |         |       |
| data       | longblob     | YES  |     | NULL    |       |
+------------+--------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql&gt; select * from config where name = 'system.theme';
+------------+--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+
| collection | name         | data                                                                                                                                                      |
+------------+--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+
|            | system.theme | a:3:{s:5:"admin";s:5:"seven";s:7:"default";s:6:"bartik";s:5:"_core";a:1:{s:19:"default_config_hash";s:43:"gOjer9hADYYnbCJVZMFZIIM1azTFWyg84ZkFDHfAbTz";}} |
+------------+--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql&gt; 



  By default, the "active" configuration is stored in the database
  ("config" table). This is for performance and security reasons. This
  is the complete configuration for the entire site at that moment.
  Configuration can be exported and imported as YAML files, either in
  it's entirety, or a single piece of configuration, using Drush config
  commands or the Configuration Manager.  


More info: https://www.drupal.org/docs/8/configuration-management/managing-your-sites-configuration