SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f967479cf35f10c36d3b26588a55822997764d57bedda997423c484c16fc44ac' 
  AND token = 'uhZIxk5lqiu73g352y8aZLi7whGEzy3QoWaZ3RivfJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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