SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '216615ecc7b508ec60e2168f7bf3de3f6f913bf92633a94f3bf8917884e1bae2' 
  AND token = 'Qk2rQnmTrvSynOLuJ+Qi5qAizcGVwwtI3YLKcBtuyK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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