SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '291bfdd01dab609670b71ef4f2110842ab561e7015e561ee9fa68abd552e26d9' 
  AND token = '10IxdQxkTipKiSGGHXRTsDDsArXAiUYJbnkZbk2cNsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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