SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6cb3064317e0d88d84126c26374b4b4006ec205cdd46afb7ab44e7fa3bc5969' 
  AND token = 'hlj0ed71nKtqx7GnOxWRQHir3pg5FDvLOr/umsZwlE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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