SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adaf3128c71b4e7d0cb39116dff68fabb7b6ef69d05cce56e82a5cec10c50b4a' 
  AND token = '7wK151eVwQZBytAgEMnCoZe0oAaLtftfZ3sVjiNCf1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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