SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddf8a178ff5757fd7c9151f97b2965ade934b2bb74c9400065a5604dc7bd4bd1' 
  AND token = 'LbQEJdL6PiaTeOEMNhCirPVNuB6MbAG8OEIEp9JID8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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