SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40ae402500ab53d417854d5568b3fd4e7b8a53061022093ccace8eaec7870831' 
  AND token = '9GgyJ6tBP/PTRbsfx0BREJMZ9pshjTOjisHKFHq+OPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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