SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a628a43425635d132ed5fa30913322c7954d824c35063554d972b94245df783' 
  AND token = 'u+OJt5m9OnOWLn8Vc16La/sOsd9eqfxIyXQ9mSK7MTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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