SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9046d276618d999bf1214a44506705cb7822fe3aa83fdccda51661246e240e2d' 
  AND token = 'qHuPK5e/UDa1ZcZRzZvQ/I5hBkjL6lPuUXYl6Nx8npA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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