SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c079334f0e10b19dbabeda4ed9465059d05f7de5712d450d939c8a353701ea' 
  AND token = 'uo1hF5W7NRoXKd/SEtFf+1x1OXKCAxxs9VPUEBBI/Z4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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