SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ebe818952bf0455e880eeedda306a3db4c5ad7a0e4f413bef142ad261250960' 
  AND token = '9r1GukTzXV+PH6kiXvwpaxlCQgoJbJ2Z/hbh/ubLZCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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