SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cbf4bdc9a3155f57ec45a08dd28edb761cc94a58f7cca56e24258829e978908' 
  AND token = 'jJF+gtNEFIuUc16ZFerGcKJUQCbxSQIeITxuQLSVrZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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