SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ef6a667fb9486b7f9207ee8b476ebf7165a3f43e4f840aa1220a49a6f373d6' 
  AND token = 'aF97jvug/6DJdNWbBgng+oWYcQKpDx6VJlrChxsEwV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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