SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eda0f1ebe1743b2c3ab29c922e63bdc644a87b78f8a53fadb882629c729341b5' 
  AND token = 'Z4pxjtMBNAxhJpmQwHQ8XhVVN/T4bE6LRv93PE+oc6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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