SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49cb071caf3565c3755289defbd046ae8e13ba1f65c4fab9157883be38227334' 
  AND token = 'gPeMvWXgjOj+LUBEpOFv4zYYa1ZJGGc/dURBRjXZXso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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