SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '066b21d55e820ef7264be41b273bbd9027bdf1cf7f06d4ebfb11f7716d150ebd' 
  AND token = '1kahSdWSa+4Y415mWQTKqUsXWrWOHA1ZHdKnev8751g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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