SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd76cc515290de455cca9c78fff4090e783594e12fc9f8f6582d1392db4abdfe' 
  AND token = 'JdxVNRZTlJsWvxllbjZmydUnaBZzhIdvOEUk5QGfV7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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