SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e4e166757c6de41d73a956062ca85f3d2b46c7b5316a696267321898d42cca8' 
  AND token = 'T/yB4eLGVyJo5EFDz2LnO1NDMH6ZIwBavoWOCce8zdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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