SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08061634d5eb5b3bcbd89569318673b7a36e7d3fc3687ac07666f7d159df26b3' 
  AND token = 'kyn8U3xHJTLYzrYyC2LtrSpmuCvj0EioEtWFzAhMCRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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