SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45bfd26b0591c0f96cdc0eb80e0e4eb9b34501c1548f40fa196bdd4b5ab9ef0c' 
  AND token = 'AUGuV16RdaiFiPmX+wQYhPGa8GQFxjNWm2/wsUDprb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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