SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c2f1955886cd2b80dc0a719f8943ed57aa31853f0482c8943677bdfb5d46f6c' 
  AND token = 'fxZF9uR17dFqogTe9wQFLGe2icV1Le4TzdJHjUnOBlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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