SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e2461e2da6178994727d145828bcfba30b4137d3a6da31927a8ea0088382f8d' 
  AND token = 'TPHlhekpC1xfxCqYMUtzKJgaCOPVSBoojuYRnZW7YlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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