SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40dfc80080aede1550e8eb8575bbba8f2f58279f4854e9d6f047206022fedc1b' 
  AND token = 'LrS0yGjJ6uXNA9mJaz9Oo+RYTw58YfG4CKrCermJmCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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