SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '277269e212dada4f34f561538aae120ecd37eb75af877ed38c8ede8357c0a968' 
  AND token = 'GaR2fJeWN9yXKXxMEzpb79Tw92zGsElXknqGURbSUeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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