SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a94a35d89f5b06c38d29d8cb6674d5335a23ad3a4b6b772e1cda674cf30c06dd' 
  AND token = 'Ki2xvlaHmmZj9iPSSQy11ngYjs5V+/9tA+spiTwDCmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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