SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dfd77825a93e378614be7c052905fd0302a6de650d7d74644cdfca58bd81f59' 
  AND token = 'nn527zQv4ZMLs+lzvHlXxXDt4265ccYzEvoPytq/nck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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