SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9af1b989f28747c787afb05206b97b127a5d76e7b81731a13ba84d323e371e41' 
  AND token = 'yaVk90M7slSDbVG+dlKgcguouka5ffcXgoZQSDIb1Ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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