SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff45b0f9413468f1d6466491fd5e28a7fd35a7080cd576cef83e826f8bcf6ee' 
  AND token = 'TcPnVB80dlJIUWHm/+UrKwKM2JMOevlYvN+Xplu+d/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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