SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '645fad14b258d258d01bdac447b15043c1799d962d3a8c31d78affd65c74ff0c' 
  AND token = 'CmKUfVWSCDLz3HGZXBqmawN26aAXAVM2tU6J8l27m7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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