SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e9df8b11a468912765d458bcb176c3eba079475058786626d528f8cbb99dce4f' 
  AND token = 'YfSdn2S+bKaA1S1KeUzR55dJZsGzl3JvW01Tk99VDSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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