SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1756c0243d1f436e82a949183302d6b9e221b4cb8048d34d30ac22e9e800f40a' 
  AND token = 'rodOX7ikV78VFz0PQws+ENmvpY9Jpe1MguKatI1TYTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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