SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44b0d366ad21f8d8fc0ef332180ab02fe07239d8dd7524daee10349cfe1c60ff' 
  AND token = '/nZmVSWsmq2LLElZJQknVvD0fMMIsdnqoxfjsFCB7tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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