SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59bbcbfe25876e5b21780bafa7000705e33a0aab4133d0f04797cbc7395087c8' 
  AND token = 'EcTmA9SQGMa7mApoQFsmNixcij8vxBtKC1MEhIkYX9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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