SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d8ee89beafe6b8c3dceda6d8492278b412f1b0724a72594cb18fab8390567a1' 
  AND token = 'zejWiBIFCWzuzzcs+EvKJKIrpBh2kLm1QtL+FLnqSos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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