SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a614d355e571ddd130d208934ac1a273578974522261b9cdfef2882830a17171' 
  AND token = 'Tg3VF5qrDD/mKCOOJLNUgFvYPWazevg5NlTbiEa9FOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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