SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63e9a43e7a979a0feaa9c35ebba0c144d5c336d64fcaa4890a3add62217b082a' 
  AND token = 'CNQ9dqhIOFRvewxPJk0EoabIX1DJvZAwaR0RqW88VHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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