SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f33947ff9f661505c57b91588472c4dd245b9c2b28e763dd165e55fc75621a6e' 
  AND token = 'ev016qOqsd8aiSLDXgVJuZ2n650E9RyN6krALYa3MkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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