SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b3efaec6fdf7bcc73d8eb2f8876a8eab9eaa6683008fdd2442a4ecb54479747' 
  AND token = 'l3pf9NakfgrGS44H82YcIYV1v3hgy5JOicLG+tpmRCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}