SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b92076658585330e8e2667321da3ee91e29345a1af9b897cfa8b172d5fa4b66d' 
  AND token = 'hb30B5K2mQLd7RLzw0/7dtiIo9/2ZGJ4L52O1Y/C7Dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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