SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f540a5e577953b8ca520a59d754476add6162303ed160c185ea683d214c933d' 
  AND token = 'KEsXL+hVbSQrcJwqOHjIwave0Yl8dq9xhLpTfyJhgfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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