SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c537289a6b9dae03534704ad2809d25fb3bb68272367d731f5d6471df23d15' 
  AND token = 'zNE4hLRsQXslnbuyUqhjVhJlbQB3GCXdMzAq959hD9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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