SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a3bee9a5f9c492909aca405197fa0ab705489d5916d9acb6d296ceec954a89' 
  AND token = 'j7NBkQzpbNnDlxCI97EzuRRQL3gWSIgFdOYs6Gpjvlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}