SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbc9d88ce63e8477c11a7c61aaee8b6163257a90c6914ff32620d371eea434d' 
  AND token = 'yJx8UzB3Zv0ZLJaCwhodwUj+5BnFhAob6/mIHqkwLdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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