SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '466f49fc2578871eded0dcc4d04d3d8d43de277045677300c05deccdca5703e4' 
  AND token = '3auOuTrhSbgbecweWIrJybtztH5h3IpdfOu3zLoVDpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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