SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03f538128214bcf912bd12829ba3b30f1afab327cedd2af95b43321759814ffa' 
  AND token = '/ZH2wV+wu5qKPnA3/+1mHS5ZYjEjTGDcEJn2Q34NvTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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