SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '607f6c0723d986ca2942188537352e2f5f033ba1d5ea6cdbfcaea27c09ad9f58' 
  AND token = 'pUntrTU/bo46b0TWOEahVKpvkiQnx5t0IWlQnc5ZaAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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