SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '850c811a178987b50d357c1b18d2865a921f167544592f8033d918ab3b3b160f' 
  AND token = 'NkyfpS9cqrYFmkE3o/H9JI7t+RSExg4bUTeqdbZWl+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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