SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f357486f03236d070c53bdc8102f27a0efe8b59487b14af49de67ff02c74b48' 
  AND token = 'abcQrbutWyFJkGTogOE5lmOTmhXeHsjWNF68hZPjNCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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