SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468056ef7041490402afc821861187f95fcc129130a1fec608ee5789b6bbdc2f' 
  AND token = 'zmsdMkYGKHVOpPBVYcuIi8LO5nWFxnT+Jv2Doq3LWmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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