SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9736381f9497c9f3e96e664c8a028e52ce1560eed8a5d4a052642f9cbe562f1f' 
  AND token = 'B1jhjU1GKYw8b/Spa7KUAauBIJplCplZUd6TN+zU3Ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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