SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c31b8695bca2099dc2ee7653bf422327240f62a90a2bfc3f31a71f22c49a56a8' 
  AND token = 'IYvrKL3KZ4LvEjN+GEK8Uit2PwXlqEQL/EAwqtahxyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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