SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'eaf08e42b6a92fed8712493974741bf895301b3226a971d34c9f365d3c751004' 
  AND token = 'prMuNu6hAw6p9KYQSYKS9zjrbLEHVqNGdFtiVUc99cU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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