SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5db849a83758f0ae1e26678287fc6a1bd8531beeeecb0aaba21e7518047c053' 
  AND token = '/aXUi7YiqKtkTqHsG51YmXCU6dieJHlNYs+EiShkgVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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