SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '156a57e4e9d1eec52a9d970ed2970e20c545aaa4af0e0d32e5daa28a5bb1a397' 
  AND token = 'an4yC95Cy0wdxCYlz3akgGiUhELZYDqIghdSvo1/JCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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