SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3971fab7b20ea46ad7e7a0f45d29b048745b3c589c682041af0ce44f67eea5d0' 
  AND token = 'kKO/nHhWRzwVOTbJ11C3urj6mXGYgTN7X5Oy5vb6tig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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