diff --git a/src/Contracts/Future/CanDeleteKeys.php b/src/Contracts/Future/CanDeleteKeys.php
index 990ed34e..50a46662 100644
--- a/src/Contracts/Future/CanDeleteKeys.php
+++ b/src/Contracts/Future/CanDeleteKeys.php
@@ -16,4 +16,4 @@ interface CanDeleteKeys
      * @return void
      */
     public function deleteMany(array $keys, Tenant $tenant = null): void;
-}
\ No newline at end of file
+}
diff --git a/src/Contracts/Future/CanFindByAnyKey.php b/src/Contracts/Future/CanFindByAnyKey.php
new file mode 100644
index 00000000..56cf77c1
--- /dev/null
+++ b/src/Contracts/Future/CanFindByAnyKey.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Stancl\Tenancy\Contracts\Future;
+
+use Stancl\Tenancy\Exceptions\TenantDoesNotExistException;
+use Stancl\Tenancy\Tenant;
+
+/**
+ * This interface *might* be part of the StorageDriver interface in 3.x.
+ */
+interface CanFindByAnyKey
+{
+    /**
+     * Find a tenant using an arbitrary key.
+     *
+     * @param string $key
+     * @param mixed $value
+     * @return Tenant
+     * @throws TenantDoesNotExistException
+     */
+    public function findBy(string $key, $value): Tenant;
+}
diff --git a/src/StorageDrivers/Database/DatabaseStorageDriver.php b/src/StorageDrivers/Database/DatabaseStorageDriver.php
index f949dee4..6baf0f8b 100644
--- a/src/StorageDrivers/Database/DatabaseStorageDriver.php
+++ b/src/StorageDrivers/Database/DatabaseStorageDriver.php
@@ -77,11 +77,11 @@ class DatabaseStorageDriver implements StorageDriver, CanDeleteKeys
      * @param string $key
      * @param mixed $value
      * @return Tenant
-     * @throws TenantCouldNotBeIdentifiedException // todo ?
+     * @throws TenantDoesNotExistException
      */
     public function findBy(string $key, $value): Tenant
     {
-        // [WIP] [TODO] Temporary implementation, key has to be a custom column.
+        // The key has to be a custom column. It's recommended to set up an index
         $tenant = Tenants::where($key, $value)->first();
 
         if (! $tenant) {
diff --git a/src/StorageDrivers/RedisStorageDriver.php b/src/StorageDrivers/RedisStorageDriver.php
index 8d5fc14a..453bd030 100644
--- a/src/StorageDrivers/RedisStorageDriver.php
+++ b/src/StorageDrivers/RedisStorageDriver.php
@@ -84,8 +84,6 @@ class RedisStorageDriver implements StorageDriver, CanDeleteKeys
         return $this->makeTenant($data);
     }
 
-    // TODO find by *
-
     public function getTenantIdByDomain(string $domain): ?string
     {
         return $this->redis->hget("domains:$domain", 'tenant_id') ?: null;
diff --git a/src/TenantManager.php b/src/TenantManager.php
index b6c27665..5e080cb9 100644
--- a/src/TenantManager.php
+++ b/src/TenantManager.php
@@ -10,6 +10,7 @@ use Illuminate\Foundation\Application;
 use Illuminate\Support\Collection;
 use Illuminate\Support\Str;
 use Illuminate\Support\Traits\ForwardsCalls;
+use Stancl\Tenancy\Contracts\Future\CanFindByAnyKeys;
 use Stancl\Tenancy\Contracts\TenantCannotBeCreatedException;
 use Stancl\Tenancy\Exceptions\NotImplementedException;
 use Stancl\Tenancy\Exceptions\TenantCouldNotBeIdentifiedException;
@@ -231,9 +232,9 @@ class TenantManager
             throw new Exception('No value supplied.');
         }
 
-        if (! method_exists($this->storage, 'findBy')) { // todo use a contract instead
+        if (! $this->storage instanceof CanFindByAnyKeys) {
             throw new NotImplementedException(get_class($this->storage), 'findBy',
-                'This method was added to storage drivers provided by the package in 2.2.0 and will be part of the StorageDriver contract in 3.0.0.'
+                'This method was added to the DB storage driver provided by the package in 2.2.0 and might be part of the StorageDriver contract in 3.0.0.'
             );
         }