SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29623b3cd9cf8a9d7c628f526341782fc4fcd45499526066156578a0f14239e8' 
  AND token = '7hIGYF6FZ8w+9yyO+VJYjQu5hUkWWwvXZDP6gkzW0co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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