SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '338433bbf5afb75f1ab2a6589cdb257fe3783af86f481ac17b6f14deb58430cf' 
  AND token = 'FVNRfK1QY/MqYiEKUVovQJSBqhmQzVO5pQ2K3UCLc7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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