SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dbe12c3d878318479679043bbb591a70e98856649b7c478389d1ab280a919403' 
  AND token = '2KvOEEnYa/mcFFM5LQhL9VcZArPhYOw+YZXCmUP4Bc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}