SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '964627a26fa64a35928244e97b762076a5bafaef2625307346f9e402d2fabe65' 
  AND token = 't0hvbKS0VQbzRKtfKIf5+Tmi0hmHVkxzfOXrnMohcGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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