SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cae4f378458378d9197e00c8e19334856bfc04ba32dd5a54fe96380ec21e93b1' 
  AND token = 'p/tJg9+RGgmgRGVn7OtI6+wzUYbBB/O0oIFxtd7zy54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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