Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e21746c317194054a41f2fc7213975392b09d63ee0430c2db202e7003fec324' 
  AND token = 'QAYahyf34D7aThhLLp9SBMNLmAI+uMNSWLuom5uwDMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}