SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c54a6405d221be87d171d5fccf9ef8dca383963aac2541cd31c5969b5e254013' 
  AND token = 'jC+nPvnYMxUaBfkB8EkQRJqgUkvS+U7kHlCfN1VJI1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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