SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3926137cae00c013f409bc6838d90eca34a572b46dc230892fe16c1930ee801' 
  AND token = 'Mu7MFkSgQvfjHWvwxBaz8ZQd9hirqHdBhqGXtlIZLsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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