SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '853ee0ae8a390c881d91ccfe0f73f6deb9bdcc9a85e0cb8b5397e37d40466776' 
  AND token = '3CH//6jsRltPIR7knwuRuvgpIFzhLSieoxEX6dvUqtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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