SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87b33e4fb5eb64a930065de5d144990043f85a8a292a13c9596b10c6b57cfec5' 
  AND token = 'XALfoTCDTjKFEog1N7bjAxJN37CFiMvdE0zVwizpjfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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