SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd71626b4e78235fceb041f0081d96bc02ddc2e11694941510228ded2505107da' 
  AND token = 'dE5HoY0NbDfc5n7r+Ltayx/4StIT4dbmIWd0IVJGVlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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