SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e29bfb3b7d0c29b548b8df794821576e798a43fe029570eb087be391be06275d' 
  AND token = 'FxBGYYRarH6dVG491ICaAClJCtfNvrVzMYmXrdGTaWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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