SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c12a792420499849893ecf156619ab7fd22cd566ce7cbdbfb5fdf4a94590792' 
  AND token = 'agDC2VG5qgz4Jz2b02jyoMTBQK4KDnOgVKgTooCMu8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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