SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecf726575cd56f92c92f28d3fe526fe9cde52dbf906a5da8ce578fe30fd5b0c3' 
  AND token = 'VW3ViuuEvFauN44X1DZV8EQUEAA/RYtgjx+bpXyvJFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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