SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98c51c05b84f9124d997c4e5a948204df66ce970903284d0a488b50ed2f020f1' 
  AND token = 'ZvJNBpqvHG4wTevEY/+Pcl1W2V3kTM5YzO4WoDKt+jU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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