SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd28a04344fbf04ddf20680d4ad2e99b2a1fea7816499c7608bc2a3cdf92282a' 
  AND token = 'RCwBxCMxXMuhh2PPmeh2bfiFp2Mr0MYkfTefSZmEHBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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