SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4775ebd21c20e5900162e1c85116221ebf8241f1b5ab14bc8f30879e3d931bf8' 
  AND token = '/sL6WSWywWweYkK9PcZq7Fe2xXyqajYXwe5e1grURRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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