SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29e2a8da5c821672ace9f046e0475b2eae73a6ec97388c7e4de8b455c65b40d1' 
  AND token = 'GNY/MUyoOM/JrTNhE1O1QRngKBbFd2DXz4632d0QSHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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