SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2916319cc1b4d720d02d017c3c73011236c1a2c5c07c1b7af037c46a03485eda' 
  AND token = 'CPq4cnmGUQXTTRNygS5iVVkSJDAlzfgu8NkRU57JVeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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