SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd665645ccafb9ef71f602673b223429d16ae28c047f4ec41c6a3e80aa4790ff4' 
  AND token = 'x6ot/OqDezGLtEKgzGPfFeknvDl2mNhqTkDzTxHxZ4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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