SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4c27b1742a3b90f89267098f221daee6fd5953b824c14b4835b51d2ddadf1bb' 
  AND token = 'AwPXHkzQB7B8ZB2zM0c49l56OsdAciqOtHasjDw4Ums=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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