SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08b52c796b373dae11f3ceae284b0377eaebf54383a964ff9907194b5aa4a8a4' 
  AND token = 'zm/UCPCICSiJpJmrz9wjzJAu4pOM2g0HbboIYDMsXQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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