SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb283657adb2f66cd6a43f08cc9c26f7dcc15f508479c5116e5ca57c9750f438' 
  AND token = 'V8pMhBMkNrLpa5Tl1patXNtxcVqi2GM0ZCKJCozpiMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}