SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd56408d8b3b0bdc85143cf3c42764c2735d4d1bc4c39ad4896bbb1c23a764211' 
  AND token = 'qBfbmFGiMzhhXqNttKuBKCnbAvXU0jD2csUhBTJZToc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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