SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40cc34a42ff6d2d973ba4b1fa70520833efeceb06027c896e9654a23fe9d5b48' 
  AND token = '6pRUYfgL1r+yjaKOnJzpAjghzpqxddQw4Rpv5A8rqdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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