SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '549a0297857994612364b462b36328a2d81e2ad45191cdcf147b450061351faa' 
  AND token = 'uBghiC/ZkWH8rjaJa8JB8t+CqIcFz1A6dRlHzVquxC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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