SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5b81f3d5c8b64a3a276e0921c4e4cbe780fb16c239e4122e3ebb59bbd690023' 
  AND token = 'CWkD1Qgnq0wQK1z0g8JwDF87aMGIUQwsH11Pfp4jtuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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