SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '765b76e91ef00ee3d1e063372e05ea0ae7e8a38812d74e8583758429eb5a801b' 
  AND token = 'JTml/S5oRmqn2/gI98vq5aNHBxVf7qXOgr8AeD20flk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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