SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f3783b0db045405f70ec7a6eafec2c84074fb06ff29022702fb885ad8f016cc' 
  AND token = 'YhB0rUl67aqGpVVNsOv/xLW0DOA0YeKholmkTdYZHWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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