SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d5d84141caf845792dec8194721ab6842f9b81043d1096904439561834b9780' 
  AND token = 'zk4yiiwG+qONOpr/TXYYkhRLvDE43rg1qEQNpGferfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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