SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0db19d6ff8c00bce8485414263920765a8c403eccfbec6ffcf089bcadfe796df' 
  AND token = 'Xs7RxVFh8n/dRHmTqLzoAWOlejGbJCfLx3Y6+81BiJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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