SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16bad255e1c8054ffa6666ecc5f36f056fac3b14e387385c3dda54daa92c3411' 
  AND token = 'RhwzMgoEwqJcn79XWjkANJb//DgqhjroymnwSyFJzVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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