SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79a65ee7c3ffc79a3e2cdc439b5d637ab20c2251454ef80d606b102bba0fb077' 
  AND token = 'thaHYauQQaDDndsipJ8lA13Ecvovs37nQfNHydoHSE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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