SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95fce651886daef7642427974ea3ef03104a473967844929f99f8a44ea71abb5' 
  AND token = 'tb7WtjbAHwyckbHPeGjKaXbYZbvF/9yXBYRqfla+RX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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