SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5c533c20c8887247820b7aadf134789085879cbfb69258f403be085eae98efc' 
  AND token = 'U2/gvLvW8aOzzVHD3KnUC9KT39IZjacEdyzOUDd47AQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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