SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dab904030c9227cdcb8b448a0bf690ca3f0051ad44aa3a380c5b9d2652fc341' 
  AND token = 'kVi8GzpglzlqL7jHuQtrPSAai+QM25LqiY0CC5HNyIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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