SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75626db131d27cca326f0cacbe0ddc761314205bc109e546b6c5b44004b7a22e' 
  AND token = 'mMkoWCoSo1OpJ3IXhmS2I+9wJsji3ubAnkyVNrcf3xY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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