SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a800c4cb8ba211ef9365b19854e45ba68f12be8d474026197ec555a7ce1f2a2' 
  AND token = 'r6TcrWDQdSbMkHh8m2hQjycY0qNzsD6Rc8S1ijMWpDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}