SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bdca69d71957061ccf39acb21cd05ba1d058a669ee9f70985b312c466f3ebca' 
  AND token = 'YK/OsCkJVX+nd+XdIKTnB+6uJ6LcCtoiryQJgVAmfwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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