SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac6ba60dd64c921f7f52815acdcbce721dd212d51aad01c41ad9f118aac8639d' 
  AND token = '3bFmHQ5wzuA+A5DfMzCTN3n7ikEWW0zvtB4QWWxNSbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}