SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69d0c8e66ab4595051198b23d34f212c85af00ebf94b96e0aa9e888d313c5051' 
  AND token = 'FdLCBI10faCCfqSsNCbzcsu0mJRsZzpeTfXmVn7Z0ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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