SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8acddebc276ef790f482b2a5b5ad27ba5c19137350500e17bff36e766b844102' 
  AND token = 'DNMF/8D/I7+lOChZCtLHRNxZ7HHmYh3/EMTVvhyuGFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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