SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6765a2b37752ea6a445e5283e882ad68b9bcc65d5799b6922d93e7cb1f0acdd4' 
  AND token = 'YfVCHEu1LVzdmykJw170YNuEzgBbDlbb5FHartPXqPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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