SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f594e87b46f3a98bd6641dc39d26f640bd37117f3e1b6e5b1ddc0ab46d2504f2' 
  AND token = 'W2BLfUJM+Z9s52oZhgOemLgR4DQxI9GclMS9uVuWhiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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