SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8d1d7fef8101ccb84e220884bc05dec9c6547557c5c6c3e893c5644179597dd' 
  AND token = 'GfdmXAp4F6IlljHXJIHYf6ozP8BafHemhMCtz8WB0bU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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