SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87d1941082ce6bdc79d96c7de1759d75b36e1f6deeca9b882144d315384d8cd7' 
  AND token = 'M/eSN6IRGu4b7fETAnT2a/XpDbv5GcQ6UOtTchXD5Mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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