SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a2331d46c8bfedc084717d35a95b728e7286381fdbfb5b2421386e0bcdd057f' 
  AND token = 'oevNM/3ObJ+6ZVKuWCSw1IJVrGh24tZB4NIeYdVcxhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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