SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30ee464d1764a6f153999897348f209335392b20c11d2bdca4c70713dc068b33' 
  AND token = 'n6dr2mq21znSNeLd01RGrpBP3h2sRwUy5YDT2VsIL6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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