SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ce08506f3a80ea3d36dbf5d8bd2518c5949da85a29e671ad468d0123a35f7f9' 
  AND token = 'mNKCRY1olmbOflRcGCXJAIxhHhHWRWthWuM5VJv5xg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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