SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bfabbf2f03783da4d46c1fb79f3e74a3d40b5300684f16472d965a549894b80' 
  AND token = 'szhOXoggj1OEZrUz4Ov1ONCIuFx2JJMm9DWwSmuZnkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}