SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c3b740c0b8e5f5946028a8665841a1fe4e981b7a07ecc07c6b94153f84f8d0a' 
  AND token = 'YohtbO/KxfUQebQ4fqK5cF/4if/r1APzr8ygjY8TBlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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