SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f67e03e4f8531963c334f555fb219155fecc05057360b581cb0c45a245a60d1e' 
  AND token = 'GUab1bpKivN0gvhkj55bilddsMR5ATcPZh6D9hV8PcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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