SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8fd47e4a27f5dcab17ccdc9feb6bfb6600f5b21f7eecbfa8eb0ef3c24425108' 
  AND token = '/BES+fsrxY5wpb2Vn965HWcOFgZPXAP9qGR1YQgXG8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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