SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dfe943232410cdbd9888d0aa007f388f0944be0af274680c165ff3f95d9d209' 
  AND token = 'lkMoSAZD7Tx5H0HFcpBzj/4dM/wrPBnCXBoq9MGgVOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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