SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c06f17b8be8ccb088dd9211184fc0aaf823b30062b0408de8fefe940ca6672a7' 
  AND token = 'WWe19t3+2GaMRUDw9qnOeDDMeWtrygiMcOdTwBnE644=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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