SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cfc44c6eb9a9b5073fae699a83a6aa294d7fa0bc3db0f1000a7337818d8d385' 
  AND token = 'eJZjDxV2cmMNDnwBMQgcpSPWYpvM+vKodwp/GeicIS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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