SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84d12bf755d2935db7354a7e515f541586af28d6b3bda3d921a0610f88db05a8' 
  AND token = '016HDURYQDdi/Q46PCUrOfVU0VmNypbRz2pkbUMnQfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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