SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b36e5bcaf1716ca5093114f1a47a452f2cf56a5ecc54bbaa4ba95d17f77ff94' 
  AND token = 'ogvAmdu50mPQ9VVan3GGAumyCvAV35Gdg0deee7o02Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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