SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fc76f160029048b5deecff8004e7d34d5104444f8127f81adb3e96910b7d9a2' 
  AND token = 'WWuQr6lpZYmDzO/ODuXv9arGl6Xcs/52huBqS2cPgPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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