SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d7e64998878ecd252a8f551217efeadec1e57e461356fbc223b8d21dfc08863' 
  AND token = 'Uv2K9lMFTQXGiKv8KeJjkY8eTlcXreK1xznbbNdEIxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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