SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2d21c2f564ad6a43f31ffed133ed367b48eab62f73fc0d2a88251f3d0dbe29da' 
  AND token = 'kfnrVY+yIXFFZ+8RNoAMxtdD7h50X7lH6/B4XF8jdpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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