SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2948f2f88f4b21434976eb92f48f97d6cbedf53a6396c682c7a7ebcaeaeb92a2' 
  AND token = 'CZ4qCORo/3tVtVukKric0v/GgaIn0mqdoF+LK5zj/8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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