SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39fb6807ad42604ccda527b88dd49864a714215fcdeafb9de6102534a6b6f1e2' 
  AND token = '8+JRZcJJo39+0J/5V2twR/UHp5ZWlvlpjTMs36rHaHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00083

JSON explain

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