SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a66ca787845a75b2f5833d7983429aef226ac680b5a4b9d637172b29b4110792' 
  AND token = 'KI0KlcraE5oja0KULOAyxraN+IUHqhKQFOYSe5hJouw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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