SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca687037ccebcb1062fe376bb385e70eb5c0a3aafcdce87c1c9a17675e1c3055' 
  AND token = 'qCbszC9iTeakv0HhjWNdLsEEKVs5YAYrSZDOmWoWyiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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