SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6990a4ed7c418e4ccb23785c536d2d5f37a125076cf7b7ee890fbbf6a05771c9' 
  AND token = 'ZXAvYWR+Irmvbhviz4bPvFgcJSghB9pOUtrePVddbRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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