SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc8253221a72163b1b47656756cbf778784226bdda5defb6f963f51209434ffe' 
  AND token = 'P72lYWfLV9koz5YIQ2aQBb4hTly5fszCKES+VZS1CzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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