SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3e6e73500e236fef801df3b1c9e9a2eae0eeb5d877e4d757e6aa443e45b20ee' 
  AND token = 'oTSs7BQTnO50JPrPx16hSGMygX7U8ya/ihXJMOV5g9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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