SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04ce938bf91f2482df4b5166f40529f256b6d8bc523b388858cddac5f71be2f9' 
  AND token = 'fkxUC0bMz5FQmHo0xGMyhWXvxKIUVPKcAzwQendFAls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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