SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adb11746e7b979279e940ae527af41ee48087fa24abfcae8520ee7f24a280d35' 
  AND token = '8/YTXLsmgmju+ary4RBr1QZtWWxUNi5ehoWbOTUhOz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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