SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '003258310e0a9a90570c4934fb65466c6b9a69a6e5dce3c18c4c6135d775e045' 
  AND token = 'T2FKiEkBGcNoQqqcHvyZ4TqSZ6LA3wphBOdSmvYWt1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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