SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81f1ad6bc79d963411f64608219f69b32c0e7d2f98461862de7a985c5c5ed73e' 
  AND token = 'YnkAIcCTF4zPnm/mLCAbXuVrKlvK9WsVmlrJ70ubbHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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