SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3db64414370b6cdd972db5850642099f2a452a8bbdb997b2a28e68b157afd6a8' 
  AND token = 'SdIj9lTOEfa93PndcRuONrxk0NbgUhYjm1yB4b1tnPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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