SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aad8febabfa595d388ef622767c6eb016eddd406e200b67688d77ebb88520717' 
  AND token = 'xZHFHQ9cNJBtVu1GCB85yLnpySiYpc7UMb1sqjj9qfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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