SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afd7eb1b7566f619cf6a3e88b798781ca0655db6d967bea9dd6967dde18a0d54' 
  AND token = 'V8E11IhFQUhDZ8ZOEGznCZ/A+C5ULlfnA3uZd/jhlhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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