SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ae79139220304bfcd1da126ba5248a06f8664607c15a245dc8a9f944decdf25' 
  AND token = 'D7kgmaYfgi4PVdKPvmHEaiXjkkiRrY6OWO/mgOq9yFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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