SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c92269378979c355b8fd1dd68e47e684a9a81cc8e6543f394d14558fdedde2a0' 
  AND token = 'Kbmr7v1ZkwCPOVIJ+D3dow+ye+ZNfT8HxsGecvkAbww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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