SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b4364c10bf0f842f4a553217b9f1306f8d56fb2dc525dd8fbbe6df15a161adc' 
  AND token = 'cy502IeDhu7J1liYZU7LMvSVW/8gU+KWQwVg7up0HbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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