SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3c6bca7cf232d0049155efd0fc158ca67b50c5c6f1993e80bb9e34f3300ba8f' 
  AND token = 'wCxZioWx53Vs6P5ZNhQQg/e/IqQIHnT2BArzRu3K3mo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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