SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d83e077874feb2fa1b39d9b80536a6ea7a41b8673f96ab5efdf3c40d2504b64' 
  AND token = 'vXDVreTUCsylvHJZXL3KOd7vcQQ+g4DlweSHHtad93U=' 
  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"
    }
  }
}