SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c56f96cb1fd7bf238462a11ef236a24aa7647ae83b676626f7aaa593aafd0cb' 
  AND token = 'vUdE7tidG4LrxJbQkFt0ygM1cStfPVP+SbynSqeMlo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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