SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ff2d2c38cd5bb58620160a19fcc79d16c251b65b14707908b94c6250ad8ec972' 
  AND token = '8aVhqowYCSbco/K6kwu5sxqASt9WCBda8ggbHGlMj9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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