SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '939b9bbbe08453de430dcf92dbba1b97d5dfcf0652910a536a19d171b93532c5' 
  AND token = 'mxGcXE6egJ8OoIKJyMY17Kx3zZ3vYQahFnphYB4nXPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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