SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61047ca6847535dd50dc863b10c802f16d5c40a44e31bbfb1ed22489a4ccdbb' 
  AND token = 'rJ6mt2jmXnZmD64Q87LA1Q6VCOjc+FwvXz9XPziqjBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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