SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a76b37192895c572a89bffabfb12832b877ff0c83d1169b472432685546ba91d' 
  AND token = 'UGe71qXrd4pxjPgJUDEEIE8090Hhr9WmRO02QyAk9hA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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