SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c306f612d4ca883610f7109052233860f940b0a3bead3933ed4c2ab0e70e14f' 
  AND token = '2jHKL28QiH+hgdkdyctieXdccAuFrFE7+OnDJudxeDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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