SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de87a84e0972cc567aae6e6d5beb193967b595e41edba25749e5fa9943bee824' 
  AND token = 'EHwhdos5T4nJjAxrjZZTprXY7yM5tCGlx8EjgMW9c2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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