SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef27ad1768dc6db0c727cbf2a4af36ef4f2749f64e327c0a0b1a92a0b20ae92' 
  AND token = 'BbF6QqzmWShbzLJHsF3w+HViVreE91cGVpYB//KgWXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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