SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f91ec61cc5b69f46169892e494e9b9d8dfa4f926675a5d92921c82d7e68bee6f' 
  AND token = 'fWhWhi9Rnpdw+lr0TxnA5GvFKV2DFQMFeGGF5/wcHbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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