SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b676ed3731929e06396cdcddea21112930c73baa657aece06b9bbaaf72ef92c0' 
  AND token = 'XlnlmCGESRpH90mvkkW2aXoPowZoqGtG+5b5hOZxbJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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