SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c75649144625eadc92b7a1ab7552f4116ff826c3d7cc30c32607b7bd2f7b568' 
  AND token = 'HuobYjZnVIfPS7POUPdBbBJIYr2VoD4pFZnx1d+OPTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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