SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '605d9e6505cb276ae89c723e1eee504bb07f09d8b16ef38447f57d138135e54f' 
  AND token = '6E8gy1ZMc6qP3LzraHh9Zp9bHJkrLluKxGLpiwh1njE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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