SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88db8d245d16999cd6701dc69b48b1d47c770c2017972f8bacc991ca9e280ef7' 
  AND token = 'qB/1JP8EFaSLeZEucdSowt2G83fdWJJzmqPKvEhQneI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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