SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03320ee96aa17c3a74482ddc720f33170043d93c62c94707b37e5d1dfa1a8e5b' 
  AND token = 'rGZ87voJLMz4AYi1NlhKMXRS8n+6F4UPl6mIwN1/ZmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}