SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1869920042e67b6b07a55a63736edbf5bef48b24b799274154a52280d8215cef' 
  AND token = 'j/wrysQnDdyYctiGmhVIEZiQPQ/73URqAAWZ8unhN6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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