SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f169af9d492ea8a236333c5b0d2392b1c89e4094d12102f5d921529b9cb785c' 
  AND token = 'arVXESqKF5Z14w9HgRhTNRfFN7PZ+xNcApWvJNTWBwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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