SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0667807d8efb5193f35ac4e5ad430ef580d584c1ad9a51b3e213fbe7af793b51' 
  AND token = 'DSKbJCsfJKaddDotmEb54ZCBkxU0N1iAEgpCY4fYU0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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