SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '686495db272f556c6b61c73d2562a9a3e1f0f5e32407caa846c33057f58eb4d9' 
  AND token = 'yXo7XZ6s6c/7HzZV0zlYNZGUrtK524j85KlUawgAO5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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