SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03daf31aa9fa31fbad966959e407d67966b985ec7ee716259e19c324aeb776c4' 
  AND token = 'f46lKbLSXU2tyercD5skiL4K3F8P/XSwX+ncorqorxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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