SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b027df114bfa268ddc632cde4849b92caef1fbdeabb89a0a8048f6d826a4f48' 
  AND token = 'dbdco6a4FWKtpdhMrZCIdgwbVbmjWxR5VjBavIiKPEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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