SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a24ff153eaa12851006bdd1cc95821626678d677c708b3ec3f9afb3af61d7be8' 
  AND token = '9DauG+SDVZelD+uKqe5pndAK/vBZQt8cOcXjCZWwaNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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