SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ecb123434a2cf42839cca4355933af404b60d9f95c5f8fb9987ac27b8084b31' 
  AND token = 'PXeW/S8YsHR04YUuRAdnrhndYDUXCKMkUKRNOPGZ2xI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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