SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fd3fe1e940c3d9e33b01f66678adb01b92752d8b4eaa6cc34312129080c887d3' 
  AND token = 'FzY5qh9WRYRynuJNC7HHmtUk1DePiaK+HTybaclbdMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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