SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dff2cddc0d698d1633b8e54c23ccb597761792b3ae3aa28d036157a100bd1d4' 
  AND token = 'LHT5JptFPP8ovLLkKmGRzkCT/u++QRaCOVS65sZgMyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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