SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2968ca11d145591445ee9e3d892be0ebccb462f933af4f4f3afe7b26b6c75478' 
  AND token = 'SJd9wAh0a8aUFKONKzQtMtYqxlWu3W0+miCV8V3vwZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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