SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46797d47c2ca724b48a66c854080c011a344ebc43d68e043250c1a78bcc2dc22' 
  AND token = 'cdznjyFj+nG/8RbTHodEvzR7XwsAfaC25GeG7gt/3uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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