SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '475f618836bd848872f211585f46fad6a47376395db22dd56f376248955a4bb0' 
  AND token = 'GWvAylgIXzQ7YS3G10Y9d9tuJgN/2AH+UOBCN3nFbAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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