SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dc0377685f96861ccf4d52570cfc1e051e5a5fd488435f8eeb3b3db7036eb3b' 
  AND token = 'HFw42MzwJetGGnlhEUDTmvMmQRxCIK1CfjfdZWVN1AU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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