SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b59a30be50aee7bc3490716855745c3e5138ccbe6a8ec00f140ee757ef1d8a0d' 
  AND token = 'ZjtsEGXKt1iSC1QWDddKj92Iau/LK1UIFAlS0QjBxIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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