SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ced694e1d720100b880eea8253cb96b3ec7b24116140dc6db11610018373c4c' 
  AND token = '9A5S2AHuUXDGYx6J+G6aHKoURnxJ4OUoormjLDXxBBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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