SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a1ce66e96c691cb586c3af9a57f5e52945afb0f9f65588996c0172f4a5fd88a' 
  AND token = 'Mtlb3I8YDdYIvUKKoB+4qNHHgjkbM4Zvrq+zAIbZAnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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