SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a3b21bb3e25b2620923fcab4ef56e3d6c270f82d97b650fbc366df4ebe01263' 
  AND token = 'wk5sN7CVbXIgdIM/LJ/LSSCASBxXZYphId2WTnru85o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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