SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b0e8f10a930700dd67bf67b69c668af271cc4d7cd4087dfbefd7ef982d82dab' 
  AND token = 'vV8yzqRg99HSRfWZU71VXUMs7K+XRmNvCWN/FgVGOws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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