SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f2685125642dffb98c2d80623c5d23d5557e86d9b8d98adc2db3629fec9c240' 
  AND token = '3QNAjMf//g5VmG5P2+53EqGCF9LvJLGJsYUjgqyDg6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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