SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '683e7c333f3768277b81778dfa1fc9225a28882875383dabdf24ced3ccd22029' 
  AND token = 'dcMW/IJjgLvbsUzxhTHZitFDIyBwFci7Pkjx/R8TdMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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