SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e2644a5a0d3e20577208be79b31885daa686cf532746a4eb99b36b594a3263f' 
  AND token = 'cb3T/e5VVJq0tak3PWo//QgHGRmIYTk3W+QzudJoBBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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