SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956c901de5b7ccf8e5e0ef97d4190469663be1c97dfdb8674b7fa23895319b34' 
  AND token = 'yp+rG4wr7STRKtYVmwDlXsk5XG9CpwwN3H9KMjL8A/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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