SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '304123aae745ec28616acc9723fde3e2f47d5e5cb730bb487cf082206297eaeb' 
  AND token = 'jw4k1LKpmKJjRw0NNwUj4WMvFjMuLqeXPYn8OliPJ+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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