SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17c0a3636051c0696d735784e982057eb1645b587b5afbf81a50078daf7ed0c5' 
  AND token = 'jWFOaRqnppLRr1o7zuw+DzlbnnitfSGuW7RfZggjAkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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