SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bc6854735460b2f658187485d68a2e68872f6940ae1d3e79d6823bacdc9e953' 
  AND token = 'y7cMVsrDzvryrm/UvIoGDreYN39g2qRUsnWbHLA7w0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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