SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f82e1cf7a6cea1f1fab48cd53cd89b6543638f5935a117b88d64764b27cb4583' 
  AND token = '3jA2KGBHWhWZK7PAXhYLclIkGTHG37orjtWmV5+dr48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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