SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2d5e96a18e4e697afad758fd25528c4d2a800a127b0a37f270c3b835198339b' 
  AND token = '1ccQxl1+sa6Hgd/O/goWsyoa8e+wb3kEFYIdfGzjgd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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