SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c249b84a92bff7852a796ced3398d2aa0011f979956078d584f5455bcb4ca676' 
  AND token = '18IVqyliubbo/e+BgaHoGXn5f/b5rCqiFq4Rg4QVxzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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