SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73caae9c61a3e784d7b620b9c3ef24c19ee0feaeee3e70293601ae73ab393289' 
  AND token = 'DEz5cxlroO/8iCnsesctOSL+Bk7qLgI0ITyvXuWHrhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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