SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b353b4b139eb1434c4bdfe677ff736f0c1f7f1455ac98573fc8d0e4341c433e0' 
  AND token = '0ZlL8M78SvaiJwaakZuZtptrk14+QRAezzD9mtKQP/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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