SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55ff6dbeab5c58a2b81d1e30b00380293765aa3cd7805280b25b09a7b561f972' 
  AND token = 'jzCI9Qyh8pbkgvsopqOPrya3tDsavyzJKAKpn3N1rrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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