SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19deb121ccc35ac82123b44209f19f8a013d9fdafdb0305c20316b7c119d90f9' 
  AND token = 'R+oJ66WpHTzFCLuu2gjR7buhwpTUropkNYQOZMBRggg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}