SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '533849e7ee938df0fc4bbe9dc308fb10b5cdb252179849c652b71f474f8a1123' 
  AND token = 'vAQhrASio/BnGsqUjqHNcj10Azx4eFan7vbzPy9XtgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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