SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42e31822c5a15af223716ae32fc83ccb4af8e2116bd83ec03063219fdf6e98df' 
  AND token = 'pYUyDsp1m145DXLLXaiWjDsM+W1wejlNcNeqdUDpV3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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