SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c76aab824553f5efe7e855a9d5cb1b9dd3e3d5aefcc874242650a3c963ea9529' 
  AND token = 'ws3GebweXWxUJJY1lOJ4YlvqXDMmZYn8f5hHFYsjRLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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