SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3bd0f1e01105176b05e1100cb91f5a937bb1eadf2ea284b8625d5d0ec6d7413' 
  AND token = 'zC461ObQXgyERWGEVmXhXGHGodicy2S8UVAsz+E/QBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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