SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83c7092d847eb5deedd69afe9a732823bbdd349251674be4f0702024d7f56632' 
  AND token = 'ZErpIz+Mxc6CWK6C5RMh1VI7lycWbLjBRqeGN0UMAc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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