SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd75844a8dd00f7396f72c656339cd67431cdf827ea340421701ea9f3f79e0514' 
  AND token = 'b+qdGRG2lyfj7AeupDx2lHq+nLCTDu7KHwUUYkZo+bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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