SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '189d568ce63b182e342f26ec09a59a8ce67e5410d5f70ffacc310bf65a2405cd' 
  AND token = '8J/3VJhWFJjUQZYRZH1jpXdzWw6hlrrEW4MpdLe5oKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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