SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33d915230af35797a84a08de068e6a6a5f637249637503a0004e1fa83edb7771' 
  AND token = '3ZuRYmCQaHsXObNlmgvNdED4iMLhkTZjhEZUSbHHuHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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