SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12d3696424af5ad1accad370b5cc1ddf1e4f590822e6b7eb61e94010ecb5698c' 
  AND token = 'wWFuVJCXXU3Z9SWVGxxqCJ/zvVmcW2S8+5Onqy2cikI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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