SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c5be542739241abbe14c8107a96566b6ce3d9b0a21b990da18b63c90cec315' 
  AND token = 'V7OEAp0Ibs8hAotvZ14AmCcQRUEcIJ76xIWXnbBjSf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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