SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa6e40be66540976f87a8d495c836d671c82db8581828718f82cffa97e94e5b7' 
  AND token = 'ljBjtFPsV54tT53m5O+/lM3kFzsjnl98bvfUi0wtV6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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