SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eae720a18f2e35758ca8b092c24d50d800921e03d84f821c022adaa5e9661c1' 
  AND token = 'MMa1Z+duHMG4FE12ZrrujcisYBp5y5GxxCfaiZ/WcDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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