SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '855c050c5cf24a7d6ad7e9a34b44f1c51cae4311804dd44b475d4f717a961f13' 
  AND token = 'yxYkKHLnmENFG++vKBhkZnDZydGTvl02qH9LUM+jltU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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