SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '505698e9caa60d27a829bd4a317c7019827576c776fc038870f8769fbb6c978c' 
  AND token = 'zvepHwFlBrXCAn7VE4jLIqiHzm+RK1h0zChx+izy/rU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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