SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3f6a91cc3157999a4bb4d2599853f810550ced9b220bafb84b195189e3d5e16' 
  AND token = 'jwodYTURUqy0l6qv0EJQoU5NgEJLUndxQeyIGVSR2+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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