Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3517f4a9f50b741547202ce6965831c9709b28f75abb6e93e01abf7d8ac0d60' 
  AND token = '+MJ7kTeI0yeB9HSyKFjUJmyCkfLvQB+FluHHQfkma9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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