SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3ec741a515a62b4cd420941180ef94ec15a8655306f5cf205af6e3f17e3cd1f' 
  AND token = '8v25Kv8DgrAMWUvZWC2aH1u6Bh//4eqHW91HhHJbM0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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