SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30ec61fd473e00242e7e44a6493a4a3858d38477107c902c6ad9c6b0cf0ccf51' 
  AND token = 'KJi9S5+10cmUmtwRNbu7c3601xhXJBUFrvdD+r2aiVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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