SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e5b175aef0e1f122ad96cc39fd896734300d02bca5ec7a77fd832a14d5b8a68' 
  AND token = 'TBX3kv8LdLQalpc5Ffgq2NOfxP3tXcOOv/OyoNidHvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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