SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a7d6ac114cc7c0c697194bf247529110b451b41c8fb2494aac47d659a0bd930' 
  AND token = 'Rv9UEgfgn8g/rHPwN7MgMbJz3UbT5hvMZmYtCkxIVrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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