SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73ca61e1d960028a6dc8daf8ae91e2e427115e1080eb22777812c7916d90ee33' 
  AND token = 'ENMEEKB7tzPH72ZB3aTXVv+j9HUSi3MVXdiwOoBvCfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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