SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf1fed527fa69a7c11ead8f131f1aa71a40dfeca1f553d7e112ab56e348ca103' 
  AND token = 'Mq09RdFqpI0z8FgQH2ZLZVo2xbSUcJo+9CQQ5lvLO8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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