SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd558666115ae9a8caf69926da0a637d5b4ddcd5e0e9407fdc5af5822258138fa' 
  AND token = '3rX8whsOZHnG4CWvWUQuWCCMpJfYZhWppZVRknpb5f4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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