SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34704413675bafd98f720682cbe42352fd253f643286f616b88d71a9bcdb9275' 
  AND token = 'RWczzWx/swtULpbXuM6G8gIkts7+ZmhsQH+ecX+1QRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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