SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad41654a6933baaa4c5222008433577f76b506b9c73ccfd77bbdc2993a4c9eea' 
  AND token = 'dzpsrfqfXAP51kKOIAj5dHLZZrP+0Dn4c4RjvugsP/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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