SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a9b02ed91bc7a3ca3b7606f444a313fce8134e1babc2b2038d1fc51b83a0166' 
  AND token = 'RKWQUPjjZd3oiNcpemK8HR6iySBSn6VtcKaxlQMxjQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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